Journal of Composites Science

Research

18 pages, 4778 KiB

Open AccessArticle

Comprehensive Investigation of Hardness, Wear and Frictional Force in Powder Metallurgy Engineered Ti-6Al-4V-SiC_p Metal Matrix Composites

by Adithya Hegde, Rajesh Nayak, Gururaj Bolar, Raviraj Shetty, Rakesh Ranjan and Nithesh Naik

J. Compos. Sci. 2024, 8(2), 39; https://doi.org/10.3390/jcs8020039 - 23 Jan 2024

Cited by 3 | Viewed by 1650

Abstract

Metal matrix composites (MMCs) have achieved significant attention in engineering applications because of their exceptional properties, like increased strength-to-weight ratiosand resistance to wear. However, their manufacturing processes pose challenges for industries, such as oxidation, porosity, and chemical reactions. To address these challenges, this [...] Read more.

Metal matrix composites (MMCs) have achieved significant attention in engineering applications because of their exceptional properties, like increased strength-to-weight ratiosand resistance to wear. However, their manufacturing processes pose challenges for industries, such as oxidation, porosity, and chemical reactions. To address these challenges, this study investigates the processing and sintering (500 °C) of Ti-6Al-4V-SiC_p composites and their mechanical properties, particularly hardness, wear and frictional force using a statistical approach. The main objective of this research is to identify optimal processing conditions for Ti-6Al-4V-SiC_p composites that yield maximum hardness, minimal wear and frictional force. Thisstudy varies three key parameters, namely compaction pressure (Ton/sq.inch), SiC (wt.%), and PVA binder (wt.%) using Taguchi’s design of experiments (TDOE). Further, the response surface methodology (RSM) is used to develop second-order models to predict the output values under different processing conditions, by correlating with the values obtained from TDOE. The results indicate that the most significant influence on the output is exerted by SiC (wt.%), followed by PVA binder (wt.%) and compaction pressure (Ton/sq.inch). To achieve higher hardness with minimal wear and frictional force during processing, SiC_p (15 wt.%), compaction pressure (4 Ton/sq.inch), and PVA binder (3 wt.%) arerecommended. Finally, microstructural analysis using (SEM) scanning electron microscope images, optical macrographs and (AFM) atomic force microscopy revealed that the inclusion of 15 wt.% SiC_p resulted in improved hardness, wear and frictional force compared to 20 wt.% SiC_p. In conclusion, this study provides valuable insights into optimizing the processing parameters of Ti-6Al-4V-SiC_p samples, enabling the production of materials with enhanced hardness and wear resistance. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 9125 KiB

Open AccessArticle

Spark Plasma Sintering and Hot Pressing of Cu+Al Powder Mixtures and Pre-Deposited Cu/Al Layers

by Dina V. Dudina, Boris B. Bokhonov, Alexander I. Gavrilov, Vladimir Yu. Ulianitsky, Arina V. Ukhina, Aigul A. Ondar, Serguei F. Tikhov and Oleg L. Smorygo

J. Compos. Sci. 2023, 7(11), 466; https://doi.org/10.3390/jcs7110466 - 7 Nov 2023

Cited by 3 | Viewed by 1962

Abstract

Reactive processing of metals is interesting for materials design and achieving new sets of properties. The transformation degree of the metals, the factor governing the properties of the material as a whole, depends on the sintering/heat treatment conditions. In the present investigation, the [...] Read more.

Reactive processing of metals is interesting for materials design and achieving new sets of properties. The transformation degree of the metals, the factor governing the properties of the material as a whole, depends on the sintering/heat treatment conditions. In the present investigation, the phase and microstructure formation of materials obtained by sintering of Cu-10 wt.% Al mixtures and layered Cu/Al structures under different modes of pressing/heating is presented. The samples were obtained via spark plasma sintering (SPS), hot pressing (HP) and pressureless sintering. The products of the interaction between the metals were Al₂Cu and Cu₉Al₄ intermetallics and Cu(Al) solid solutions. The influence of the consolidation method on the phase composition of the sintered materials was studied. The hardness of the composites was analyzed in relation to their structural features. A model experiment has been conducted to trace the structural evolution at the Cu/Al interface caused by interdiffusion. The Cu/Al layered structures obtained by detonation spraying of the powders on a steel substrate were treated by SPS or HP. The effect of electric current, which is a feature of SPS processing, was in accelerating the reaction product formation in the layered structures still containing the starting metallic reactants. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 3426 KiB

Open AccessArticle

Metallic Iron or a Fe-Based Glassy Alloy to Reinforce Aluminum: Reactions at the Interface during Spark Plasma Sintering and Mechanical Properties of the Composites

by Dina V. Dudina, Vyacheslav I. Kvashnin, Boris B. Bokhonov, Mikhail A. Legan, Aleksey N. Novoselov, Yuliya N. Bespalko, Alberto Moreira Jorge, Jr., Guilherme Y. Koga, Arina V. Ukhina, Alexandr A. Shtertser, Alexander G. Anisimov and Konstantinos Georgarakis

J. Compos. Sci. 2023, 7(7), 302; https://doi.org/10.3390/jcs7070302 - 23 Jul 2023

Cited by 4 | Viewed by 1225

Abstract

The microstructural features and mechanical properties of composites formed by spark plasma sintering (SPS) of Al + 20 vol.% Fe and Al + 20 vol.% Fe₆₆Cr₁₀Nb₅B₁₉ (glassy alloy) mixtures composed of micrometer-sized particles are presented. The [...] Read more.

The microstructural features and mechanical properties of composites formed by spark plasma sintering (SPS) of Al + 20 vol.% Fe and Al + 20 vol.% Fe₆₆Cr₁₀Nb₅B₁₉ (glassy alloy) mixtures composed of micrometer-sized particles are presented. The interaction between the mixture components was studied by differential thermal analysis and through examining the microstructure of composites sintered at two different SPS pressures. When the pressure was increased from 40 MPa to 80 MPa, the thickness of the reaction products formed between the iron particles and aluminum increased due to a more intimate contact between the phases established at a higher pressure. When the metallic glass was substituted for iron, the pressure increase had an opposite effect. It was concluded that local overheating at the interface in the case of Al + 20 vol.% Fe₆₆Cr₁₀Nb₅B₁₉ composites governed the formation of the product layers at 40 MPa. The influence of the nature of reinforcement on the mechanical properties of the composites was analyzed, for which sintered materials with similar microstructural features were compared. In composites without the reaction products and composites with thin layers of the products, the hardness increased by 13–38% relative to the unreinforced sintered aluminum, the glassy alloy and iron inclusions producing similar outcomes. The effect of the nature of added particles on the hardness and compressive strength of composites was seen when the microstructure of the material was such that an efficient load transfer mechanism was operative. This was possible upon the formation of thick layers of reaction products. Upon compression, the strong glassy cores experienced fracture, the composite with the glassy component showing a higher strength than the composite containing core-shell structures with metallic iron cores. Full article

(This article belongs to the Special Issue Metal Composites)

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12 pages, 4405 KiB

Open AccessArticle

Effect of ECAP on Microstructure, Mechanical Properties, Corrosion Behavior, and Biocompatibility of Mg-Ca Alloy Composite

by Song-Jeng Huang, Chih-Feng Wang, Murugan Subramani and Fang-Yu Fan

J. Compos. Sci. 2023, 7(7), 292; https://doi.org/10.3390/jcs7070292 - 14 Jul 2023

Cited by 6 | Viewed by 1689

Abstract

This study investigates the effects of incorporating MgO into magnesium–calcium (Mg-Ca) alloy composites and subjecting them to the equal channel angular pressing (ECAP) process on the resulting mechanical and corrosive properties, as well as biocompatibility. Initially, the incorporation of MgO into the Mg-Ca [...] Read more.

This study investigates the effects of incorporating MgO into magnesium–calcium (Mg-Ca) alloy composites and subjecting them to the equal channel angular pressing (ECAP) process on the resulting mechanical and corrosive properties, as well as biocompatibility. Initially, the incorporation of MgO into the Mg-Ca alloy composites did not yield significant improvements in grain refinement, tensile strength, or corrosion rate reduction, despite exhibiting improved biocompatibility. However, upon subjecting the Mg-Ca-MgO alloy composites to the ECAP process, noteworthy outcomes were observed. The ECAP process resulted in substantial grain refinement, leading to significant improvements in tensile strength. Furthermore, a marked decrease in corrosion rate was observed, indicating enhanced corrosion resistance. Additionally, the biocompatibility of the Mg-Ca-MgO alloy composites improved after undergoing the ECAP process. These findings highlight the synergistic effect of incorporating MgO and employing the ECAP process, providing valuable insights into the development of advanced magnesium-based materials with superior mechanical properties, reduced corrosion rates, and improved biocompatibility. Full article

(This article belongs to the Special Issue Metal Composites)

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17 pages, 8678 KiB

Open AccessArticle

Electrical Characterization of Carbon Nanotube Reinforced Silver and Copper Composites for Switching Contacts

by Bruno Alderete, Frank Mücklich and Sebastian Suarez

J. Compos. Sci. 2023, 7(7), 284; https://doi.org/10.3390/jcs7070284 - 11 Jul 2023

Cited by 2 | Viewed by 1443

Abstract

Carbon nanotube (CNT)-reinforced silver and copper metal matrix composites—at three different reinforcement phase concentrations (0.5 wt.%, 0.75 wt.%, and 1 wt.%)—were produced via powder metallurgy and sintered via hot uniaxial pressing. Optical and electron microscopy techniques were used to characterize the powder mixtures [...] Read more.

Carbon nanotube (CNT)-reinforced silver and copper metal matrix composites—at three different reinforcement phase concentrations (0.5 wt.%, 0.75 wt.%, and 1 wt.%)—were produced via powder metallurgy and sintered via hot uniaxial pressing. Optical and electron microscopy techniques were used to characterize the powder mixtures and sintered composites. The latter were also electrically characterized via load-dependent electrical contact resistance (ECR) and surface fatigue tests. Particle size and morphology play a crucial role in CNT deposition onto the metallic powder. CNT were deposited exceptionally well onto the dendritic copper powder regardless of its larger size (compared with the silver flakes) due to the higher surface area caused by the grooves and edges of the dendritic structures. The addition of CNT to the metallic matrices improved their electrical performance, in general outperforming the reference material. Higher CNT concentrations produced consistently low ECR values. In addition, high CNT concentrations (i.e., 1 wt.%) show exceptional contact repeatability due to the elastic restitutive properties of the CNT. The reproducibility of the contact surface was further evaluated by the fatigue tests, where the composites also showed lower ECR than the reference material, rapidly reaching steady-state ECR within the 20 fatigue cycles analyzed. Full article

(This article belongs to the Special Issue Metal Composites)

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16 pages, 15609 KiB

Open AccessArticle

TEM Study of a Layered Composite Structure Produced by Ion-Plasma Treatment of Aluminum Coating on the Ti-6Al-4V Alloy

by Aleksey Nikolaev, Kamil’ Ramazanov, Almaz Nazarov, Vener Mukhamadeev, Elena Zagibalova and Elena Astafurova

J. Compos. Sci. 2023, 7(7), 271; https://doi.org/10.3390/jcs7070271 - 30 Jun 2023

Cited by 3 | Viewed by 1363

Abstract

Using the methods of transmission electron microscopy and energy-dispersive spectroscopy, we study the microstructure and phase composition of the coating and modified intermetallic layers obtained in a Ti-6Al-4V alloy by the deposition of the Al coating and subsequent processing in low-pressure non-self-sustained arc [...] Read more.

Using the methods of transmission electron microscopy and energy-dispersive spectroscopy, we study the microstructure and phase composition of the coating and modified intermetallic layers obtained in a Ti-6Al-4V alloy by the deposition of the Al coating and subsequent processing in low-pressure non-self-sustained arc discharge plasma (CIPT—complex ion-plasma treatment). The deposition of the aluminum coating on the Ti-6Al-4V alloy is accompanied by the formation of a layered and a gradient microstructure: nanocrystalline near the “coating/substrate” interface and ultrafine-grained in the outer part of the aluminum coating, with α-stabilized region of ≈5 µm thick in the surface layer in base titanium alloy. After the CIPT, the coating and the surface of the base titanium alloy have a layered morphology: each of the layers possesses different grain structure and composition. In the direction from the outer surface of the specimen to the base material, the following phase sequence has been confirmed by diffraction and elemental analysis: TiAl₃ → TiAl₃ + nc-(Al(Ti) + α-Ti) → nc-(Al(Ti) + α-Ti) → TiAl₃ → TiAl₃ + TiAl → TiAl → Ti₃Al → α-Ti alloy → (α + β)-Ti alloy. The nanocrystalline aluminum layer, which has been formed during the deposition of the aluminum coating, does not undergo phase transformation and recrystallization under the CIPT. Nanocrystalline structure can favor the interdiffusion of the elements between the coating and base material, and stimulate phase transformation in coarser grains situated under and over it. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 4519 KiB

Open AccessArticle

Experimental Investigation on Bio-Machining of Nickel, Titanium and Nitinol (Shape Memory Alloys) Using Acidithiobacillus ferrooxidans Microorganisms

by Mani Pradeep, Shangumavel Rajesh, Marimuthu Uthayakumar, Chandrasekar Mathalai Sundaram, Kinga Korniejenko, Krzysztof Miernik and Mohd Shukry Abdul Majid

J. Compos. Sci. 2023, 7(6), 262; https://doi.org/10.3390/jcs7060262 - 20 Jun 2023

Cited by 2 | Viewed by 1275

Abstract

Micromachining plays a vital role in the manufacturing industry in producing microcomponents with high sensitivity and fine dimensional tolerances for implant materials in medical applications. Micro-machining can be carried out through various machining processes like physical, chemical and biological processes, although the use [...] Read more.

Micromachining plays a vital role in the manufacturing industry in producing microcomponents with high sensitivity and fine dimensional tolerances for implant materials in medical applications. Micro-machining can be carried out through various machining processes like physical, chemical and biological processes, although the use of biological machining is limited. In biological machining, microorganisms are used as a source of energy to machine the components, and machining with microorganism brings a lot of advantages in the machining process like the production of components with lower energy resources, low cost, no heat-affected zone and fine dimensional tolerances, which makes it suitable for machining implant materials. In other machining process like conventional and unconventional machining processes, the heat-affected zone, dimensional tolerances and environmental-related problems are the major issues, as these processes generate more heat while machining. This damages the material, which will not be able to be used for certain applications, and this issue can be overcome by bio-machining. In this present work, nickel, titanium and nitinol are manufactured using the powder metallurgy technique. They are manufactured as a 10 mm diameter and 5 mm thick pellet. The fabricated nickel, titanium and nitinol shape memory alloys are machined with Acidithiobacillus ferrooxidans microorganisms to obtain a better material removal rate and surface roughness and to check the bio-machining performance by considering various parameters such as shaking speed, temperature, pH and percentage of ferric content for the future scope of biomedical applications. Considering these parameters, microorganisms play a vital role in the temperature, shaking speed and time of the bio-machining process, and it was observed that a better material removal rate and surface roughness are achieved at a temperature of 30 °C, shaking speed of 140 rpm and machining time of 72 h. Full article

(This article belongs to the Special Issue Metal Composites)

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12 pages, 4056 KiB

Open AccessArticle

The Influence of Nitrogen Flow Rate on the Structure and Properties of Mo-Hf-Y-Si-B-N Coatings

by Philipp Kiryukhantsev-Korneev, Alina Sytchenko, Fedor Chudarin, Boris Senatulin and Evgeny Levashov

J. Compos. Sci. 2023, 7(6), 253; https://doi.org/10.3390/jcs7060253 - 17 Jun 2023

Viewed by 1522

Abstract

This work is devoted to the production of Mo-Hf-Y-Si-B-N coatings using magnetron sputtering with varying N₂ flow rate; the analysis of magnetron discharge plasma; and the investigation of the structure, and optical, mechanical, and tribological characteristics, as well as crack resistance and [...] Read more.

This work is devoted to the production of Mo-Hf-Y-Si-B-N coatings using magnetron sputtering with varying N₂ flow rate; the analysis of magnetron discharge plasma; and the investigation of the structure, and optical, mechanical, and tribological characteristics, as well as crack resistance and oxidation resistance, of the coatings. The results show that Mo-Hf-Y-Si-B-N coatings were characterized by a dense, homogeneous structure. The non-reactive coatings had a maximum growth rate of 270 nm/min. An increase in the flow rate of N₂ from 0 to 37.5 sccm led to a decrease in the growth rate by 5.4 times. Mo-Hf-Y-Si-B-N coatings were X-ray amorphous. In non-reactive coatings, the presence of Mo-Si and Mo-B bonds was revealed. The introduction of nitrogen contributed to the formation of an additional Si-N bond, an increase in the proportion of which led to an increase in transmittance. The Mo-Hf-Y-Si-B coating was characterized by a hardness value of 14 GPa. The maximum hardness of 16 GPa was observed in coatings obtained at nitrogen flow rates of 12.5 and 25.0 sccm. A further increase in the consumption of N₂ to 37.5 sccm led to a decrease in hardness by 38%. The coating obtained at a flow rate of 25 sccm N₂ was characterized by maximum elastic recovery of 57%, elastic strain to failure of 0.098, and resistance to plastic deformation of 0.157 GPa. An increase in nitrogen flow rate from 0 to 12.5 sccm contributed to a decrease in the wear rate of coatings under sliding friction conditions by 40%. The non-reactive Mo-Hf-Y-Si-B coating had the best oxidation resistance at 1000 °C. Full article

(This article belongs to the Special Issue Metal Composites)

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12 pages, 2574 KiB

Open AccessArticle

Design and Analysis of an Automobile Disc Brake Rotor by Using Hybrid Aluminium Metal Matrix Composite for High Reliability

by Mandeep Singh, Harish Kumar Garg, Sthitapragyan Maharana, Appusamy Muniappan, M. K. Loganathan, Tien V. T. Nguyen and V. Vijayan

J. Compos. Sci. 2023, 7(6), 244; https://doi.org/10.3390/jcs7060244 - 12 Jun 2023

Cited by 9 | Viewed by 3584

Abstract

Due to their superior capabilities for manufacturing lightweight automotive components, aluminium metal matrix composites have gained a lot of attention in the last few years. Aluminium metal matrix composites are an exceptional class of metal matrix composites that can solve all the major [...] Read more.

Due to their superior capabilities for manufacturing lightweight automotive components, aluminium metal matrix composites have gained a lot of attention in the last few years. Aluminium metal matrix composites are an exceptional class of metal matrix composites that can solve all the major problems related to the automobile industry. Aluminium matrix composites in the disc braking system have already been employed and studied by many scientists. However, the developed materials are not yet always sufficiently accurate and reliable. In this article, a new enhanced metal matrix composite material is used and studied to improve the efficiency of an ordinary car’s braking system. To improve the accuracy of the designated braking system, an innovative hybrid aluminium matrix composite (Al6061/SiC/Gr)-based brake rotor has been developed, and its effectiveness has been determined by finite element analysis. From the simulation, the product performance confirmed that the hybrid aluminium matrix composite (Al6061/SiC/Gr)-based brake rotor has the potential to replace the standard cast iron brake disc. The new enhanced hybrid composite material used in this study can be used for the efficient design of various braking parts. Full article

(This article belongs to the Special Issue Metal Composites)

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17 pages, 4938 KiB

Open AccessArticle

The Effect of Laser Shock Processing on the Anti-Corrosion Performance of LENS-Fabricated Ti-6Al-4V Alloy

by Nana Kwamina Kum Arthur, Sharlotte Mamatebele Kubjane, Abimbola Patricia Idowu Popoola, Bathusile Nelisiwe Masina and Sisa Lesley Pityana

J. Compos. Sci. 2023, 7(6), 218; https://doi.org/10.3390/jcs7060218 - 26 May 2023

Cited by 2 | Viewed by 1382

Abstract

Titanium alloys are prone to increased oxidation rates when exposed to higher temperatures during application. As a result, the components suffer mechanical failure due to the formation of the alpha-case layer at 500 °C. To improve its corrosion and oxidation properties, and ultimately [...] Read more.

Titanium alloys are prone to increased oxidation rates when exposed to higher temperatures during application. As a result, the components suffer mechanical failure due to the formation of the alpha-case layer at 500 °C. To improve its corrosion and oxidation properties, and ultimately its mechanical performance, it is necessary to modify its surface properties. In this study, a LENS 3D-printing system was used to fabricate titanium alloy sample coupons, while surface treatment was performed using laser shock processing (LSP) to improve the surface properties. The characterisation of the samples was performed to establish a basis for the corrosion behaviour of the 3D-printed material and the effect of LSP treatment on the rate of corrosion. The samples fabricated at the moderate laser energy density of 249 J/mm³ showed the best-performing properties as the microstructures that evolved showed elevated hardness profiles, which were associated with material property improvements such as high strength and corrosion resistance. After subjecting the samples to LSP treatment, the properties of the LENS samples showed a further improvement in corrosion resistance. Full article

(This article belongs to the Special Issue Metal Composites)

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16 pages, 8506 KiB

Open AccessArticle

Structure and Oxidation Resistance of Mo-Y-Zr-Si-B Coatings Deposited by DCMS and HIPIMS Methods Using Mosaic Targets

by Alina D. Sytchenko, Pavel A. Loginov, Alla V. Nozhkina, Evgeny A. Levashov and Philipp V. Kiryukhantsev-Korneev

J. Compos. Sci. 2023, 7(5), 185; https://doi.org/10.3390/jcs7050185 - 4 May 2023

Cited by 3 | Viewed by 1507

Abstract

In this study, Mo-(Y,Zr)-Si-B coatings were obtained by direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HIPIMS) using mosaic targets. The results showed that the addition of Y and Zr into the composition of Mo-Si-B coatings led to the suppression of [...] Read more.

In this study, Mo-(Y,Zr)-Si-B coatings were obtained by direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HIPIMS) using mosaic targets. The results showed that the addition of Y and Zr into the composition of Mo-Si-B coatings led to the suppression of columnar grain growth, a decrease in the crystallite size of h-MoSi₂ phase from ~50 to ~5 nm, and an increase in the amorphous to crystalline phases ratio Doping of the Mo-Si-B coating with Y and Zr promoted an increase in oxidation resistance at a temperature of 1000 °C. The introduction of yttrium into the composition of Mo-Si-B contributed to an increase in their crack resistance when heated to 1300 °C. High oxidation resistance of the coatings was provided by a defect-free SiO₂ + MoO₃ + Y₂O₃ surface layer. The transition from the DCMS mode to HIPIMS decreased the texture of the Mo-Si-B coatings. The use of an HIPIMS mode led to a decrease in the oxidation rate of Mo-(Y)-Si-B coatings at T = 1000 °C by 1.6–4.5 times compared to DCMS. In the case of Mo-Y-Si-B coatings, the use of HIPIMS led to a decrease of more than 50% in the thickness of the oxide layer at a temperature of 1300 °C. Full article

(This article belongs to the Special Issue Metal Composites)

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15 pages, 9339 KiB

Open AccessArticle

Investigation of the Characteristics of MAO Coatings Formed on Ti6Al4V Titanium Alloy in Electrolytes with Graphene Oxide Additives

by Sergey Grigoriev, Nikita Peretyagin, Andrey Apelfeld, Anton Smirnov, Alevtina Rybkina, Ekaterina Kameneva, Artem Zheltukhin, Mikhail Gerasimov, Marina Volosova, Oleg Yanushevich, Natella Krikheli and Pavel Peretyagin

J. Compos. Sci. 2023, 7(4), 142; https://doi.org/10.3390/jcs7040142 - 6 Apr 2023

Cited by 7 | Viewed by 1725

Abstract

Coatings with a thickness from ~40 to ~50 µm on Ti6Al4V titanium alloy were formed by micro-arc oxidation in a silicate-hypophosphite electrolyte with additions of graphene oxide. Micro-arc oxidation treatment was carried out in the anode–cathode mode (50 Hz) with a ratio of [...] Read more.

Coatings with a thickness from ~40 to ~50 µm on Ti6Al4V titanium alloy were formed by micro-arc oxidation in a silicate-hypophosphite electrolyte with additions of graphene oxide. Micro-arc oxidation treatment was carried out in the anode–cathode mode (50 Hz) with a ratio of anode to cathode currents of 1:1, a total density of 20 A/dm², and a treatment duration of 30 min. The effect of the graphene oxide concentration in electrolytes on the thickness, roughness, hardness, surface morphology, structure, composition of micro-arc oxidation coatings, and its electrochemical corrosion behavior in 3.5% NaCl solution was studied. The input of graphene oxide additives into the base silicate hypophosphite electrolyte led to an increase in the hardness of micro-arc oxidation coatings. Electrochemical polarization studies and impedance data showed that the best characteristics in terms of corrosion-protective ability among coatings formed in electrolytes with graphene oxide additives were those formed in the electrolyte with a graphene oxide concentration of 0.1 g·L^−l. A further increase in the graphene oxide concentration in the electrolyte did not improve the protective properties of micro-arc oxidation coatings. Full article

(This article belongs to the Special Issue Metal Composites)

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11 pages, 3637 KiB

Open AccessArticle

Influence of Alternating Current Density on the Mechanical Behavior and Microstructure of PEO-Coated 7075 Aluminum Alloy

by Tumur Ochir Erdenebat, Lkhagvaa Telmenbayar, Daejeong Yang, Minjung Song, Adam Gopal Ramu and Dongjin Choi

J. Compos. Sci. 2023, 7(2), 50; https://doi.org/10.3390/jcs7020050 - 1 Feb 2023

Cited by 2 | Viewed by 1816

Abstract

The objective of the study was to investigate the characteristics of coatings formed on 7075 Al alloy using a plasma electrolytic oxidation (PEO) method in silicate electrolytes under alternating current conditions. The properties of the coatings were evaluated based on the current density [...] Read more.

The objective of the study was to investigate the characteristics of coatings formed on 7075 Al alloy using a plasma electrolytic oxidation (PEO) method in silicate electrolytes under alternating current conditions. The properties of the coatings were evaluated based on the current density applied during the experimental process. To analyze the samples, the surface and cross-sectional images of the coatings were observed using scanning electron microscopy. The results showed that the PEO coatings were between 25–102 µm in thickness, and the thickness was found to be dependent on the applied current density. The hardness values of the PEO coatings were found to be significantly, approximately three times, higher than the uncoated alloy. Wear analysis revealed that the PEO coatings formed under current densities of 8.8 A/dm² and 17.8 A/dm² exhibited the best wear resistance among all the coatings. In addition, the PEO coatings also displayed good corrosion resistance, with the resistance of the coatings formed under the current densities of 13.5 A/dm² and 17.8 A/dm² being significantly improved compared to that of the bare Al alloy. The most effective anticorrosion PEO coating was found to be the one formed under a current density of 17.8 A/dm². The wear depths of the PEO coatings formed under current densities of 8.8 A/dm² and 17.8 A/dm² were low, resulting in high wear resistance. Among all the PEO coatings, the coating formed under a current density of 17.8 A/dm² showed the best overall anticorrosion and mechanical properties. Overall, the study highlights the potential of PEO coatings in significantly improving the corrosion and wear resistance of 7075 Al alloy. The results of the study provide useful information for the selection of current density for the PEO coating process on 7075 Al alloy to achieve desired properties. Full article

(This article belongs to the Special Issue Metal Composites)

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15 pages, 14662 KiB

Open AccessArticle

Improved Wear and Corrosion Resistance in TiC-Reinforced SUS304 Stainless Steel

by Chieh-Jung Lu and Jien-Wei Yeh

J. Compos. Sci. 2023, 7(1), 34; https://doi.org/10.3390/jcs7010034 - 11 Jan 2023

Cited by 2 | Viewed by 2235

Abstract

Herein, the vacuum arc-melting process is applied to incorporate various amounts of Ti and C into SUS304 austenitic stainless steel based on the high-entropy alloy concept to obtain wear- and corrosion-resistant alloys with in situ carbide reinforcements. Five compositions containing the equivalent of [...] Read more.

Herein, the vacuum arc-melting process is applied to incorporate various amounts of Ti and C into SUS304 austenitic stainless steel based on the high-entropy alloy concept to obtain wear- and corrosion-resistant alloys with in situ carbide reinforcements. Five compositions containing the equivalent of 5, 10, 15, 20, and 25 volume percentages of TiC in SUS304 stainless steel, named A1, A2, A3, A4, and A5, respectively, were designed, melted, and solidified by the arc-melting method. Microstructural analyses, hardness measurements, immersion tests in four corrosive solutions, electrochemical measurements in a 3.5 wt % NaCl_(aq) solution, and tribological tests were conducted to determine the properties and explain the relevant mechanisms. A1 exhibited a eutectic structure between FCC dendrites, while A2, A3, A4, and A5 possessed proeutectic dendritic TiC, FCC dendrites enveloping the TiC dendrites, and a eutectic structure. A5 represents the optimal composition. Its hardness, wear resistance, and corrosion resistance are 2, 14, and 4 times higher than those of SUS304, respectively. Additionally, its wear resistance is 2.5 times that of high-chromium cast iron. Consequently, A5 could have a 2.5-fold longer lifetime in wear operation. Therefore, A5 could be potentially applied in corrosive and abrasive environments, such as rotary shafts, rotors, bearings, and structural parts in food, chemical, and optoelectronic industries. Full article

(This article belongs to the Special Issue Metal Composites)

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16 pages, 6100 KiB

Open AccessArticle

Influence of Cutting Speed during the Turning of Inconel 718 on Oxidation Wear Pattern on the Zr-ZrN-(Zr,Mo,Al)N Composite Nanostructured Coating

by Alexey Vereschaka, Filipp Milovich, Nikolay Andreev, Mars Migranov, Islam Alexandrov, Alexander Muranov, Maxim Mikhailov and Aslan Tatarkanov

J. Compos. Sci. 2023, 7(1), 18; https://doi.org/10.3390/jcs7010018 - 6 Jan 2023

Cited by 1 | Viewed by 1726

Abstract

The properties and oxidation wear patterns in the composite nanostructured coating of Zr-ZrN-(Zr,Mo,Al)N were studied during the turning of Inconel 718 alloy at the cutting speeds of v_c = 125 and 200 m/min. The hardness of the coating, its elastic modulus, and [...] Read more.

The properties and oxidation wear patterns in the composite nanostructured coating of Zr-ZrN-(Zr,Mo,Al)N were studied during the turning of Inconel 718 alloy at the cutting speeds of v_c = 125 and 200 m/min. The hardness of the coating, its elastic modulus, and critical fracture load during the scratch testing were determined. The study focused on the tribological properties of the Zr-ZrN-(Zr,Mo,Al)N coating at temperatures of 400–900 °C paired with an insert made of Inconel 718, which exhibited a certain advantage over the reference coatings of Zr-ZrN and Ti-TiN-(Ti,Cr,Al)N of similar thickness. The coating of Zr-ZrN-(Zr,Mo,Al)N provided for the longest tool life at the cutting speed of v_c = 125 m/min (the tool life was four times longer in comparison with that of the uncoated tool and 15% longer in comparison with that of the Ti-TiN-(Ti,Cr,Al)N-coated tool) and at the cutting speed of v_c = 200 m/min (the tool life was 2.5 times longer in comparison with that of the uncoated tool and 75% longer in comparison with that of the Ti-TiN-(Ti,Cr,Al)N-coated tool). While at the cutting speed of v_c = 125 m/min, the surface coating layers exhibit only partial oxidation of the external layers (to a depth not exceeding 250 nm), with mostly preserved cubic nitride phases, and then the cutting speed of v_c = 200 m/min leads to almost complete oxidation (to the depth of at least 500 nm), however, with a partially preserved nanolayered structure of the coating. Full article

(This article belongs to the Special Issue Metal Composites)

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12 pages, 4127 KiB

Open AccessArticle

Lead-Free Multiferroic Barium-Calcium Zirconate-Titanate & Doped Nickel Ferrite Composites

by Inna V. Lisnevskaya, Inga A. Aleksandrova and Artem N. Savinov

J. Compos. Sci. 2023, 7(1), 2; https://doi.org/10.3390/jcs7010002 - 20 Dec 2022

Cited by 1 | Viewed by 1851

Abstract

Magnetoelectric lead-free composite ceramic based on the piezoelecrtic Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ (BCZT) and magnetic NiCo_0.02Cu_0.02Mn_0.1Fe_1.8O_4−d (NCCMF) has been obtained by the solid state method using preliminarily synthesized [...] Read more.

Magnetoelectric lead-free composite ceramic based on the piezoelecrtic Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ (BCZT) and magnetic NiCo_0.02Cu_0.02Mn_0.1Fe_1.8O_4−d (NCCMF) has been obtained by the solid state method using preliminarily synthesized by the solid-state method precursors. X-ray diffraction measurements, microstructural, magnetic, dielectric, piezoelectric and magnetoelectric studies have been carried out. Impurity phases were not contained in the composites, and there were no signs of interfacial interaction even at the doping level. Ceramics has a high electrical resistivity at direct current (~10⁹ Ω·cm) and, over the entire range of x studied, exhibits a combination of magnetic and piezoelectric parameters, which vary over a wide range and clearly depend on the composites composition. The maximum magnetoelectric coupling coefficient ΔE/ΔH ≈ 90 mV/(cm·Oe) at a frequency of 1 kHz has been observed for specimens with x = 60–70%. Full article

(This article belongs to the Special Issue Metal Composites)

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12 pages, 4395 KiB

Open AccessArticle

Microstructural Evaluation and Fracture Behavior of AZ31/Nb₂O₅ Metal Matrix Composite

by Song-Jeng Huang, Manas Sarkar and Sathiyalingam Kannaiyan

J. Compos. Sci. 2022, 6(12), 390; https://doi.org/10.3390/jcs6120390 - 14 Dec 2022

Cited by 2 | Viewed by 2240

Abstract

There have been remarkable improvements in the research field of magnesium over the last few decades, especially in the magnesium metal matrix composite in which micro and nanoparticles are used as reinforcement. The dispersion phase of nanoparticles shows a better microstructural morphology than [...] Read more.

There have been remarkable improvements in the research field of magnesium over the last few decades, especially in the magnesium metal matrix composite in which micro and nanoparticles are used as reinforcement. The dispersion phase of nanoparticles shows a better microstructural morphology than pure magnesium. The magnesium metal matrix nanocomposite shows improved strength with a balance of plasticity as compared to the traditional magnesium metal matrix composite. In this research, Nb₂O₅ (0 wt.%, 3 wt.%, and 6 wt.%) nanoparticles were used to reinforce AZ31 with the stir casting method, followed by heat treatment, and finally, an investigation was conducted using microstructural analysis. Factors such as the degree of crystallinity, crystallite size, and dislocation density are affected by the concentration of Nb₂O₅ and heat treatment. With the compositional increase in Nb₂O₅ weight percentage, the grain size decreases up to 3% Nb₂O₅ and then increases gradually. The SEM image analysis showed a grain size reduction of up to 3% Nb₂O₅ and fracture morphology changed from basal slip to a mixture of basal slip and adiabatic shear band. Full article

(This article belongs to the Special Issue Metal Composites)

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17 pages, 6505 KiB

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Preparation of Ag/C Nanocomposites Based on Silver Maleate and Their Use for the Analysis of Iodine Ions

by Igor E. Uflyand, Marina O. Gorbunova, Vladimir A. Zhinzhilo, Tatiana S. Kolesnikova, Anastasiya O. Zarubina, Rose K. Baimuratova and Gulzhian I. Dzhardimalieva

J. Compos. Sci. 2022, 6(12), 384; https://doi.org/10.3390/jcs6120384 - 12 Dec 2022

Cited by 1 | Viewed by 1690

Abstract

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In the present study, a detailed analysis of the preparation of Ag/C nanocomposites through the thermolysis of silver maleate was carried out. Thermolysis products are nanocomposites containing silver nanoparticles (NPs) uniformly distributed [...] Read more.

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In the present study, a detailed analysis of the preparation of Ag/C nanocomposites through the thermolysis of silver maleate was carried out. Thermolysis products are nanocomposites containing silver nanoparticles (NPs) uniformly distributed in a stabilizing carbon matrix. The composition, structure, and properties of the obtained nanocomposites were studied using IR-spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). This article reports on the possibility of using Ag/C nanocomposites to create new indicator papers that are sensitive to iodide ions in the concentration range of 0.03–1.6 mg/L (0.24–12.6 μM). The developed papers are used in a technique based on the oxidation of iodides with the formation of molecular iodine, which is extracted in an air stream and transferred to a sensitive paper layer containing silver NPs. The interaction of silver NPs with iodine leads to optical changes that can be tracked using a conventional scanner. Full article

(This article belongs to the Special Issue Metal Composites)

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11 pages, 4162 KiB

Open AccessArticle

First-Principles Calculations of Crystallographic and Electronic Structural Properties of Au-Cu Alloys

by Dung Nguyen Trong, Van Cao Long, Umut Saraç, Van Duong Quoc and Ştefan Ţălu

J. Compos. Sci. 2022, 6(12), 383; https://doi.org/10.3390/jcs6120383 - 12 Dec 2022

Cited by 6 | Viewed by 2168

Abstract

In this research, we have explored the effect of Au:Cu ratio on the crystallographic and electronic structural properties, formation energies, and radial distribution function (RDF) of Au-Cu alloy materials via density functional calculations. The results show that Au-Cu alloy can be formed in [...] Read more.

In this research, we have explored the effect of Au:Cu ratio on the crystallographic and electronic structural properties, formation energies, and radial distribution function (RDF) of Au-Cu alloy materials via density functional calculations. The results show that Au-Cu alloy can be formed in any Au:Cu ratio from 3:1 to 1:3 with a similar possibility. The results also reveal that the lattice constants of both Au and Cu are affected by the LDA-PWC pseudo-field, which is in full agreement with the experimental findings. An increase in the concentration of Cu impurity in Au results in a decrement not only in the lattice constants of the crystal system but also in the total energy of the system (E_tot). However, an enhancement in the electron density is determined by increasing Cu impurity concentration in Au. The RDF results confirm the contraction of lattice constants and a structural change in Au-Cu from cubic to tetrahedral is found when the Au:Cu ratio is equal to 1:1. These findings revealed in this work are expected to contribute to future studies on electronic materials. Full article

(This article belongs to the Special Issue Metal Composites)

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18 pages, 15505 KiB

Open AccessArticle

Specific Application Features of Ti-TiN-(Ti,Cr,Al)N, Zr-ZrN-(Zr,Mo,Al)N, and ZrHf-(Zr,Hf)N-(Zr,Hf,Cr,Mo,Al)N Multilayered Nanocomposite Coatings in End Milling of the Inconel 718 Nickel-Chromium Alloy

by Alexey Vereschaka, Filipp Milovich, Nikolay Andreev, Mars Migranov, Islam Alexandrov, Alexander Muranov, Maxim Mikhailov and Aslan Tatarkanov

J. Compos. Sci. 2022, 6(12), 382; https://doi.org/10.3390/jcs6120382 - 12 Dec 2022

Cited by 1 | Viewed by 1552

Abstract

This article discusses the specific application features of end mills with Ti-TiN-(Ti,Cr,Al)N, Zr-ZrN-(Zr,Mo,Al)N, and ZrHf-(Zr,Hf)N-(Zr,Hf,Cr,Mo,Al)N multilayer nanocomposite coatings during the machining of the Inconel 718 nickel–chromium alloy. The hardness, fracture resistance during scratch testing, structure, and phase composition of the coatings were studied. [...] Read more.

This article discusses the specific application features of end mills with Ti-TiN-(Ti,Cr,Al)N, Zr-ZrN-(Zr,Mo,Al)N, and ZrHf-(Zr,Hf)N-(Zr,Hf,Cr,Mo,Al)N multilayer nanocomposite coatings during the machining of the Inconel 718 nickel–chromium alloy. The hardness, fracture resistance during scratch testing, structure, and phase composition of the coatings were studied. The tribological properties of the samples were compared at temperatures of 400–900 °C. Tests were conducted to study the wear resistance of the coated end mills during the milling of the Inconel 718 alloy. The wear mechanism of the end mills was studied. It was found that in comparison with the other coatings, the Zr-ZrN-(Zr,Mo,Al)N coating had the highest hardness and the lowest value of the adhesion component of the coefficient of friction at high temperatures. However, the Zr-ZrN-(Zr,Mo,Al)N coating exhibited good resistance to cracking and oxidation during the milling of the Inconel 718 alloy. Based on the above, the Zr-ZrN-(Zr,Mo,Al)N coating can be considered a good choice as a wear-resistant coating for the end milling of the Inconel 718 alloy. Full article

(This article belongs to the Special Issue Metal Composites)

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9 pages, 1651 KiB

Open AccessArticle

Studies of the Application of Electrically Conductive Composite Copper Films to Cotton Fabrics

by Ramshad Abzhalov, Malik Sataev, Shaizada Koshkarbayeva, Guzaliya Sagitova, Bakyt Smailov, Abdugani Azimov, Bagdagul Serikbaeva, Olga Kolesnikova, Roman Fediuk and Mugahed Amran

J. Compos. Sci. 2022, 6(11), 349; https://doi.org/10.3390/jcs6110349 - 12 Nov 2022

Cited by 4 | Viewed by 1540

Abstract

This paper presents a technology for applying copper and silver films to cotton fabrics by combining photochemical and chemical methods for the reduction of the compounds of these metals. The resulting metal-containing films have inherent electrical conductivity of metals. All the main processes [...] Read more.

This paper presents a technology for applying copper and silver films to cotton fabrics by combining photochemical and chemical methods for the reduction of the compounds of these metals. The resulting metal-containing films have inherent electrical conductivity of metals. All the main processes described in the work were carried out by means of the compounds being sorbed by the surface of the fabric when they were wetted in appropriate solutions. The aim of the work was to study the application of electrically conductive composite copper films on cotton fabrics. The tasks to achieve this aim were to perform scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis to confirm that as a result of the experiment, CuCl with a semiconductor ability was formed on the surface of the sample. The driving force behind the photochemical reduction of copper and silver halides on cotton surfaces is that, as a result of the photooxidation of cellulose molecules in the fabric, copper monochloride is first formed on the cotton surface. Subsequently, the process of obtaining silver particles based on semiconductor silver chloride obtained as a result of the transformation of copper monochloride was carried out. The physicochemical and photochemical processes leading to the formation of monovalent copper chloride, which provides sufficient adhesion to the substrate, are considered. It is shown that in this case, the oxidation of monovalent copper also occurs with the formation of soluble salts that are easily removed by washing. Since the proposed technology does not require special equipment, and the chemical reagents used are not scarce, it can be used to apply bactericidal silver films to various household items and medical applications in ordinary laundries or at home. This article examines an affordable and simple technology for producing metal films on a cotton surface due to the presence of disadvantages (time duration, high temperature, scarce reagents, special installations, etc.) of a number of well-known methods in the production of chemical coatings. Full article

(This article belongs to the Special Issue Metal Composites)

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13 pages, 3444 KiB

Open AccessArticle

Enhanced Photocatalytic Degradation of Amoxicillin with Mn-Doped Cu₂O under Sunlight Irradiation

by Yohannes Teklemariam Gaim, Simachew Mekides Yimanuh and Zaid Girmay Kidanu

J. Compos. Sci. 2022, 6(10), 317; https://doi.org/10.3390/jcs6100317 - 17 Oct 2022

Cited by 20 | Viewed by 2998

Abstract

In this work, we report the synthesis of Mn-doped Cu₂O nanoparticles using aloe vera leaves extract. X-ray diffraction data revealed that the Mn-doped Cu₂O crystals have a cubic crystal structure. The surface morphology of the as-synthesized catalyst indicated truncated [...] Read more.

In this work, we report the synthesis of Mn-doped Cu₂O nanoparticles using aloe vera leaves extract. X-ray diffraction data revealed that the Mn-doped Cu₂O crystals have a cubic crystal structure. The surface morphology of the as-synthesized catalyst indicated truncated octahedral and spherical-like shapes. The photocatalytic activity of the catalyst is efficient at pH 9, initial concentration of amoxicillin 15 mg/L, and photocatalyst dosage 1 g/L under sunlight irradiation. 92% of amoxicillin was degraded in the presence of Mn-doped Cu₂O. The enhancement in photocatalytic performance is due to the incorporation of Mn, which delays the rapid recombination rate by trapping the photogenerated electron. Therefore, Mn-doped Cu₂O could remove pharmaceuticals from pharmaceutical factory and hospital wastes. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 6179 KiB

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Synthesis and Catalytic Activity in the Hydrogenation Reaction of Palladium-Doped Metal-Organic Frameworks Based on Oxo-Centered Zirconium Complexes

by Rose K. Baimuratova, Anastasia V. Andreeva, Igor E. Uflyand, Gennadii V. Shilov, Farida U. Bukharbayeva, Alima K. Zharmagambetova and Gulzhian I. Dzhardimalieva

J. Compos. Sci. 2022, 6(10), 299; https://doi.org/10.3390/jcs6100299 - 9 Oct 2022

Cited by 3 | Viewed by 1982

Abstract

Metal-nanocluster-doped porous composite materials are attracting considerable research attention, due to their specific catalytic performance. Here we report a simple, cheap, and efficient strategy for the preparation of palladium hydrogenation catalysts based on metal-organic frameworks (MOFs). It has been shown that the synthesis [...] Read more.

Metal-nanocluster-doped porous composite materials are attracting considerable research attention, due to their specific catalytic performance. Here we report a simple, cheap, and efficient strategy for the preparation of palladium hydrogenation catalysts based on metal-organic frameworks (MOFs). It has been shown that the synthesis of Pd/MOF results in the formation of palladium nanoparticles uniformly fixed on the surface. The composition and structure of the resulting composites were studied using elemental analysis, DSC, TGA, XRD, TEM, and IR spectroscopy. Pd nanoparticles with an average diameter of 8–12 nm were successfully confined in the UiO-type MOFs, and the obtained nanocomposites exhibited abundant porosity, high stability, and a large surface area. It has been shown that the resulting catalytic systems with high activity, selectivity, and stability reduce phenylacetylene and allyl alcohol to styrene and propanol, respectively, in liquid-phase hydrogenation reactions. Full article

(This article belongs to the Special Issue Metal Composites)

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17 pages, 7564 KiB

Open AccessArticle

An Eco-Friendly, Simple, and Inexpensive Method for Metal-Coating Strontium onto Halloysite Nanotubes

by Anusha Elumalai and David K. Mills

J. Compos. Sci. 2022, 6(9), 276; https://doi.org/10.3390/jcs6090276 - 17 Sep 2022

Cited by 2 | Viewed by 1834

Abstract

Osteoporosis increases the risk of bone fracture by reducing bone mass and thereby increasing bone fragility. The addition of strontium (Sr) nanoparticles in bone tissue results in a strengthening of the bone, induction bone formation by osteoblasts, and reduction of bone reabsorption by [...] Read more.

Osteoporosis increases the risk of bone fracture by reducing bone mass and thereby increasing bone fragility. The addition of strontium (Sr) nanoparticles in bone tissue results in a strengthening of the bone, induction bone formation by osteoblasts, and reduction of bone reabsorption by osteoclasts. The use of Sr for bone tissue regeneration has gained significant research interest in recent years due to its beneficial properties in treating osteoporotic-induced bone loss. We hypothesized that Sr-coated and antibiotic-doped HNTs could be used in antimicrobial coatings and as an antibacterial drug delivery vehicle. Accordingly, we coated HNTs with strontium carbonate (SrHNT) using a simple, novel, and effective electrodeposition method. We tested the antibacterial properties of SrHNT on Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermis using the disc diffusion method. We assessed the potential cytotoxic and proliferative effects of SrHNTs on pre-osteoblasts using a Live/Dead cytotoxicity and cell proliferation assay. We successfully coated HNTs with strontium using a one-step benign coating method that does not produce any toxic waste, unlike most HNT metal-coating methods. Antibacterial tests showed that the SrHNTs had a pronounced growth inhibition effect, and cell culture studies using MC 3T3 cells concluded that SrHNTs are cytocompatible and enhance cell proliferation. Full article

(This article belongs to the Special Issue Metal Composites)

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16 pages, 4255 KiB

Open AccessArticle

Crafting Metal Surface Morphology to Prevent Formation of the Carbon–Steel Interfacial Composite

by Yuanhuan Zheng, Siok Wei Tay and Liang Hong

J. Compos. Sci. 2022, 6(9), 266; https://doi.org/10.3390/jcs6090266 - 9 Sep 2022

Viewed by 1586

Abstract

We created a coke-repellent inner surface in a stainless steel (SS-321) tube using an enhanced chemical etching tactic. A water-borne etching solution was formulated by combining an ion sequestering ligand (L), hydrogen peroxide (H), hydrochloric acid (C), and a stabilizing agent (E or [...] Read more.

We created a coke-repellent inner surface in a stainless steel (SS-321) tube using an enhanced chemical etching tactic. A water-borne etching solution was formulated by combining an ion sequestering ligand (L), hydrogen peroxide (H), hydrochloric acid (C), and a stabilizing agent (E or N). Three etchants, LHC, LHC-E, and LHC-N, were therefore formulated, respectively. The coke-repellent metal surfaces achieved by these etchants all show a characteristic topographic pattern on a micron scale, specifically with grooved spherulite and ridge-like topographic patterns. Fundamentally, these two topographic patterns prompt overhead micro turbulence fields whose agitation mitigates the surface entrapment of aromatic hydrocarbon flocs generated from the overhead lubricant. The surface entrapment of flocs is the crucial step to trigger coke growth. The coke repellency was assessed by placing an SS-321 tube filled with a lubricant in a heat soak. It was found that the topographic pattern and its surface roughness level have opposite effects on coke development. Hence, the three etchants give rise to different coke-resilient surfaces. Moreover, the plug flow rate of the etchant also affects the anti-coking performance, exhibiting an optimal flow rate that offers the highest coke-proof efficacy. Full article

(This article belongs to the Special Issue Metal Composites)

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13 pages, 1534 KiB

Open AccessArticle

Determination of Young Modulus and Stress-Strain Curve for Metal Fe and Interstitial Alloy FeC

by Nguyen Quang Hoc, Dung Nguyen Trong, Nguyen Chinh Cuong, Bui Duc Tinh, Nguyen Duc Hien, Van Cao Long, Umut Saraç and Ştefan Ţălu

J. Compos. Sci. 2022, 6(9), 250; https://doi.org/10.3390/jcs6090250 - 26 Aug 2022

Cited by 7 | Viewed by 2175

Abstract

In this research, the numerical calculation for elastic and nonlinear strains of Fe metal and FeC alloy under different pressures has been performed by the statistical moment method SMM with Mie–-Lennard–Jones potential (MLJ) and Embedded-Jones potential Atom Method (EAM). The analysis reveals that [...] Read more.

In this research, the numerical calculation for elastic and nonlinear strains of Fe metal and FeC alloy under different pressures has been performed by the statistical moment method SMM with Mie–-Lennard–Jones potential (MLJ) and Embedded-Jones potential Atom Method (EAM). The analysis reveals that an enhancement in the concentration (cC) from 0 to 5% causes a decrement in the Young’s modulus (E) at room temperature (T = 300 K) for FeC. These calculated results are consistent with the experimental results. In addition, the obtained stress-strain curves for Fe are in perfect agreement with the experimental curves. Besides, increasing the cC for a continuous strain decreases the stress, showing that adding C to Fe to form FeC steel will increase strength and hardness, but decrease elasticity and hardness. The results obtained will be very useful not only for experimental studies but also for theoretical studies of metals and their interstitial alloys. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 5778 KiB

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Simple Approach to the Fabrication of Lanthanum Orthoniobates and Nanocomposites with Ni, Cu, and Co Metal Nanoparticles Using Supercritical Isopropanol

by Dinara Altynbekova, Yuliya Bespalko, Konstantin Valeev, Nikita Eremeev, Ekaterina Sadovskaya, Tamara Krieger, Artem Ulihin, Arina Uhina, Bakytgul Massalimova, Mikhail Simonov and Vladislav Sadykov

J. Compos. Sci. 2022, 6(9), 243; https://doi.org/10.3390/jcs6090243 - 23 Aug 2022

Cited by 2 | Viewed by 1926

Abstract

Orthoniobates of rare-earth elements are a promising group of materials attractive for the design of nanocomposite hydrogen separation membranes owing to a perspective type of proton conductivity, good mechanical properties, and high stability in H₂O- and CO₂-containing atmospheres. In [...] Read more.

Orthoniobates of rare-earth elements are a promising group of materials attractive for the design of nanocomposite hydrogen separation membranes owing to a perspective type of proton conductivity, good mechanical properties, and high stability in H₂O- and CO₂-containing atmospheres. In general, the promising method involves the synthesis of nanocomposites with transition metals (Cu, Ni, and Cu-Ni alloys) and their oxides with high electronic conductivity. For the first time, lanthanum orthoniobates and nanocomposites with NiCu and NiCo nanoparticles were synthesized using alcohol solutions of salts of the corresponding metals by the solvothermal method in a flow reactor in a supercritical isopropanol medium. This method made it possible to obtain single-phase La_0.99Ca_0.01NbO_4–δ oxide. The introduction of doping titanium cations did not allow obtaining a single-phase La_0.99Ca_0.01Nb_0.98Ti_0.02O_4–δ sample, as impurities in lanthanum methaniobate and La₂Ti₂O₇ were found. Calcined powders and gastight pellets of orthoniobates and nanocomposites were characterized by X-ray diffraction analysis as well as scanning and transmission electron microscopy. Transport characteristics were investigated by the Van der Pauw technique, varying measurement temperatures in a wet H₂ atmosphere. The oxygen mobility was estimated by the oxygen isotope heteroexchange with C¹⁸O₂. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 3728 KiB

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Strain Control of Magnetic Anisotropy in Yttrium Iron Garnet Films in a Composite Structure with Yttrium Aluminum Garnet Substrate

by Ying Liu, Peng Zhou, Rao Bidthanapally, Jitao Zhang, Wei Zhang, Michael R. Page, Tianjin Zhang and Gopalan Srinivasan

J. Compos. Sci. 2022, 6(7), 203; https://doi.org/10.3390/jcs6070203 - 12 Jul 2022

Cited by 1 | Viewed by 2400

Abstract

This report is on the nature of strain in thin films of yttrium iron garnet (YIG) on yttrium aluminum garnet (YAG) substrates due to film-substrate lattice mismatch and the resulting induced magnetic anisotropy. Films with thickness 55 nm to 380 nm were deposited [...] Read more.

This report is on the nature of strain in thin films of yttrium iron garnet (YIG) on yttrium aluminum garnet (YAG) substrates due to film-substrate lattice mismatch and the resulting induced magnetic anisotropy. Films with thickness 55 nm to 380 nm were deposited on (100), (110), and (111) YAG substrates using pulsed laser deposition (PLD) techniques and characterized by structural and magnetic characterization techniques. The in-plane strain determined to be compressive using X-ray diffraction (XRD). It varied from −0.12% to −0.98% and increased in magnitude with increasing film thickness and was relatively large in films on (100) YAG. The out-of-plane strain was tensile and also increased with increasing film thickness. The estimated strain-induced magnetic anisotropy field, found from XRD data, was out of plane; its value increased with film thickness and ranged from 0.47 kOe to 3.96 kOe. Ferromagnetic resonance (FMR) measurements at 5 to 21 GHz also revealed the presence of a perpendicular magnetic anisotropy that decreased with increasing film thickness and its values were smaller than values obtained from XRD data. The PLD YIG films on YAG substrates exhibiting a perpendicular anisotropy field have the potential for use in self-biased sensors and high-frequency devices. Full article

(This article belongs to the Special Issue Metal Composites)

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16 pages, 1826 KiB

Open AccessArticle

Zirconium Containing Periodic Mesoporous Organosilica: The Effect of Zr on CO₂ Sorption at Ambient Conditions

by Chamila A. Gunathilake, Rohan S. Dassanayake, Chacrawarthige A. N. Fernando and Mietek Jaroniec

J. Compos. Sci. 2022, 6(6), 168; https://doi.org/10.3390/jcs6060168 - 9 Jun 2022

Cited by 8 | Viewed by 2077

Abstract

Two series of zirconium-incorporated-periodic-mesoporous-organosilica (Zr–PMO) materials were successfully prepared, via a co-condensation strategy, in the presence of Pluronic P123 triblock copolymer. The first series of Zr–PMO was prepared using tris[3-(trimethoxysilyl)propyl]isocyanurate (ICS), tetraethylorthosilicate (TEOS), and zirconyl chloride octahydrate(ZrCO), denoted as Zr-I-PMO, where I refers [...] Read more.

Two series of zirconium-incorporated-periodic-mesoporous-organosilica (Zr–PMO) materials were successfully prepared, via a co-condensation strategy, in the presence of Pluronic P123 triblock copolymer. The first series of Zr–PMO was prepared using tris[3-(trimethoxysilyl)propyl]isocyanurate (ICS), tetraethylorthosilicate (TEOS), and zirconyl chloride octahydrate(ZrCO), denoted as Zr-I-PMO, where I refers to ICS. The second series was synthesized using bis(triethoxysilyl)benzene (BTEE), TEOS, and ZrCO as precursors, named as Zr-B-PMO, where B refers to BTEE. Zr–PMO samples exhibit type (IV) adsorption isotherms, with a distinct H2-hysteresis loop and well-developed structural parameters, such as pore volume, pore width, high surface area, and narrow pore-size distribution. Structural properties were studied by varying the Zr:Si ratio, adding TEOS at different time intervals, and changing the amount of block copolymer-Pluronic P123 used as well as the calcination temperature. Surface characteristics were tailored by precisely controlling the Zr:Si ratio, upon varying the amount of TEOS present in the mesostructures. The addition of TEOS at different synthesis stages, notably, enhanced the pore size and surface area of the resulting Zr-I-PMO samples more than the Zr-B-PMO samples. Changing the amount of block copolymer, also, played a significant role in altering the textural and morphological properties of the Zr-I-PMO and Zr-B-PMO samples. Optimizing the amount of Pluronic P123 added is crucial for tailoring the surface properties of Zr–PMOs. The prepared Zr–PMO samples were examined for use in CO₂ sorption, at ambient temperature and pressure (25 °C, 1.2 bar pressure). Zr–PMO samples displayed a maximum CO₂ uptake of 2.08 mmol/g, at 25 °C and 1.2 bar pressure. However, analogous zirconium samples, without any bridging groups, exhibited a significantly lower CO₂ uptake, of 0.72 mmol/g, under the same conditions. The presence of isocyanurate- and benzene-bridging groups in Zr-I-PMO and Zr-B-PMO samples enhances the CO₂ sorption. Interestingly, results illustrate that Zr–PMO materials show potential in capturing CO₂, at ambient conditions. Full article

(This article belongs to the Special Issue Metal Composites)

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11 pages, 3695 KiB

Open AccessArticle

Negative Thermal Expansion Properties of Sm_0.85Sr_0.15MnO_3-δ

by Yucheng Li, Yang Zhang, Yongtian Li and Yifeng Wu

J. Compos. Sci. 2022, 6(6), 156; https://doi.org/10.3390/jcs6060156 - 25 May 2022

Cited by 1 | Viewed by 2128

Abstract

A novel negative thermal expansion (NTE) material composed of Sm_0.85Sr_0.15MnO_3-δ was synthesized using the solid-state method. By allowing Sr²⁺ to partially replace Sm³⁺ in SmMnO₃, the ceramic material Sm_0.85Sr_0.15MnO_3-δ [...] Read more.

A novel negative thermal expansion (NTE) material composed of Sm_0.85Sr_0.15MnO_3-δ was synthesized using the solid-state method. By allowing Sr²⁺ to partially replace Sm³⁺ in SmMnO₃, the ceramic material Sm_0.85Sr_0.15MnO_3-δ exhibits NTE properties between 360K and 873K, and its average negative thermal expansion coefficient was −10.08 × 10⁻⁶/K. The structure of Sm_0.85Sr_0.15MnO_3-δ is orthogonal, the space group is pbnm, the morphology is regular, and the grain size is uniform. The results of X-ray diffraction and XPS (X-ray photoelectron spectroscopy) suggest that the NTE phenomenon is related to the electron transfer of Mn ions. With the increase in temperature, Mn⁴⁺ is rapidly transformed into Mn³⁺, accompanied by Mn⁴⁺O₆ octahedron distortion and oxygen defects. It was found that the sample volume continually decreased at the same time. Full article

(This article belongs to the Special Issue Metal Composites)

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17 pages, 8495 KiB

Open AccessArticle

Molecular Dynamics Study of Melting Behavior of Planar Stacked Ti–Al Core–Shell Nanoparticles

by Huadian Zhang, Yu-Chen Su, Yiwei Han and Shan Jiang

J. Compos. Sci. 2022, 6(5), 126; https://doi.org/10.3390/jcs6050126 - 26 Apr 2022

Cited by 3 | Viewed by 2692

Abstract

Selective laser sintering (SLS) is one of the most commonly used methods in additive manufacturing, due to its high prototyping speed and applicability to various materials. In the present work, molecular dynamics (MD) simulations were performed to study the thermodynamic behaviors of the [...] Read more.

Selective laser sintering (SLS) is one of the most commonly used methods in additive manufacturing, due to its high prototyping speed and applicability to various materials. In the present work, molecular dynamics (MD) simulations were performed to study the thermodynamic behaviors of the planar stacked nanoparticles (NPs) model and explore the potential capability of the SLS process with nano-sized metal powders in the zero-gravity space environment. A multi-particle model of titanium–aluminum (Ti–Al) core–shell NP with a particle radius of 50 Å was constructed to investigate the characteristics of the melted pattern during sintering. Two patterns with different spatial densities were considered to study the influence of particle stacking on the melting process. Various core volume fractions and heating rates were examined to investigate their effects on the quality of the final sintered product. The stacked-NPs models with core volume fractions (CVFs) of 3%, 12%, and 30% were linearly heated up to 1100 K from room temperature (298 K) with heating rates of 0.04, 0.2, 0.5, and 1.0 K ps⁻¹. The initial fusion temperature and final sintering temperature for each stacking pattern were obtained via the validation from the radial distribution function, mean squared displacement, and the radius of the gyration analysis. The 30% CVF yields the largest neck size before the melting point, while beyond the melting point, a larger core helps delay the formation of the fully-melted products. It is observed that using the close-packed stacked-NPs model under a slow heating rate (long melting duration) would help form a stable, completely sintered product with a relatively low final sintering temperature. Full article

(This article belongs to the Special Issue Metal Composites)

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21 pages, 3305 KiB

Open AccessArticle

Nonlocal Free Vibrations of Metallic FGM Beams

by Maria A. R. Loja, Katarzyna Rzeszut and Joaquim I. Barbosa

J. Compos. Sci. 2022, 6(5), 125; https://doi.org/10.3390/jcs6050125 - 25 Apr 2022

Cited by 3 | Viewed by 2143

Abstract

This work aims to analyse the free-vibration response of functionally graded, simply supported beams with different gradient directions, taking into account nonlocal effects. To this purpose, the first-order shear deformation theory and the nonlocal elasticity theory of Eringen are used, in order to [...] Read more.

This work aims to analyse the free-vibration response of functionally graded, simply supported beams with different gradient directions, taking into account nonlocal effects. To this purpose, the first-order shear deformation theory and the nonlocal elasticity theory of Eringen are used, in order to assess the influence of size dependency effects on the free-vibration responses of those beams. The influence of other factors such as the aspect ratio of the beams and the evolution of the constituents’ mixture through the beam thickness and along its length is also considered. In this last case, a mixture distribution is proposed, accounting for the boundary conditions’ characteristics. The finite element model is first verified against existing alternative solutions, to assess and illustrate its performance. Based on the conclusions achieved, a set of parametric studies is then developed. The results are discussed considering the material distribution profiles, and conclusions are drawn with respect to their relative performance under the analysed conditions. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 2575 KiB

Open AccessArticle

A Facile In Situ Synthesis of Resorcinol-Mediated Silver Nanoparticles and the Fabrication of Agar-Based Functional Nanocomposite Films

by Yeong-Ju Bang, Swarup Roy and Jong-Whan Rhim

J. Compos. Sci. 2022, 6(5), 124; https://doi.org/10.3390/jcs6050124 - 24 Apr 2022

Cited by 7 | Viewed by 2778

Abstract

The in situ synthesis of silver nanoparticles (AgNPs) was performed using resorcinol and agar to produce agar-based antioxidant and antimicrobial films. AgNPs were regularly dispersed on the film matrix, and their presence improved the thermal stability of films. Additionally, the addition of AgNPs [...] Read more.

The in situ synthesis of silver nanoparticles (AgNPs) was performed using resorcinol and agar to produce agar-based antioxidant and antimicrobial films. AgNPs were regularly dispersed on the film matrix, and their presence improved the thermal stability of films. Additionally, the addition of AgNPs slightly increased the agar-based film’s tensile strength (~10%), hydrophobicity (~40%), and water vapor barrier properties (~20%) at 1.5 wt% of AgNP concentration. The resorcinol also imparted UV-barrier and antioxidant activity to the agar-based film. In particular, the agar-based film containing a higher quantity of AgNPs (>1.0 wt%) was highly effective against the foodborne pathogenic bacteria L. monocytogenes and E. coli. Therefore, agar-based composite films with improved physicochemical and functional properties may be promising for active packaging. Full article

(This article belongs to the Special Issue Metal Composites)

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9 pages, 1536 KiB

Open AccessArticle

Solar-Light-Driven Ag₉(SiO₄)₂NO₃ for Efficient Photocatalytic Bactericidal Performance

by Malaa M. Taki, Rahman I. Mahdi, Amar Al-Keisy, Mohammed Alsultan, Nabil Janan Al-Bahnam, Wan Haliza Abd. Majid and Gerhard F. Swiegers

J. Compos. Sci. 2022, 6(4), 108; https://doi.org/10.3390/jcs6040108 - 6 Apr 2022

Cited by 1 | Viewed by 2532

Abstract

Photocatalytic materials are being investigated as effective bactericides due to their superior ability to inactivate a broad range of dangerous microbes. In this study, the following two types of bacteria were employed for bactericidal purposes: Gram-negative Escherichia coli (E. coli) and [...] Read more.

Photocatalytic materials are being investigated as effective bactericides due to their superior ability to inactivate a broad range of dangerous microbes. In this study, the following two types of bacteria were employed for bactericidal purposes: Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The shape, crystal structure, element percentage, and optical properties of Ag₉(SiO₄)₂NO₃ were examined after it was successfully synthesized by a standard mixing and grinding processing route. Bactericidal efficiency was recorded at 100% by the following two types of light sources: solar and simulated light, with initial photocatalyst concentration of 2 µg/mL, and 97% and 95% of bactericidal activity in ultra-low photocatalyst concentration of 0.2 µg/mL by solar and simulated light, respectively, after 10 min. The survival rate was studied for 6 min, resulting in 99.8% inhibition at the photocatalyst dose of 2 µg/mL. The mechanism of bactericidal efficiency was found to be that the photocatalyst has high oxidation potential in the valence band. Consequently, holes play a significant part in bactericidal efficiency. Full article

(This article belongs to the Special Issue Metal Composites)

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13 pages, 3000 KiB

Open AccessArticle

Evaluation of Mechanical and Wear Properties of Al 5059/B₄C/Al₂O₃ Hybrid Metal Matrix Composites

by Uppu Pranavi, Pathapalli Venkateshwar Reddy, Sarila Venukumar and Muralimohan Cheepu

J. Compos. Sci. 2022, 6(3), 86; https://doi.org/10.3390/jcs6030086 - 9 Mar 2022

Cited by 16 | Viewed by 3359

Abstract

There is a developing interest in efficient materials in automobile and aerospace fields that involves the improvement of metal matrix composites (MMCs) with great properties which incorporate higher strength, hardness and stiffness, better wear and destructive resistance along with better thermal properties. This [...] Read more.

There is a developing interest in efficient materials in automobile and aerospace fields that involves the improvement of metal matrix composites (MMCs) with great properties which incorporate higher strength, hardness and stiffness, better wear and destructive resistance along with better thermal properties. This work deals with the evaluation of the mechanical and wear properties of the newly developed hybrid MMC of Al 5059/B₄C/Al₂O₃ produced by stir casting method. The main aim of the work was to evaluate the mechanical properties of various MMCs fabricated with various weight proportions of ceramic particles (B₄C and Al₂O₃). An increase in the tensile strength and the surface hardness was observed with the increase in the ceramic particles but there was a decrease in the percentage of elongation of the specimen. An increase in the ceramic content in the composite samples made the composite sample brittle (composite) from ductile (base metal). Full article

(This article belongs to the Special Issue Metal Composites)

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18 pages, 5642 KiB

Open AccessArticle

Metal/Carbon-Fiber Hybrid Composites—Damage Evolution and Monitoring of Isothermal Fatigue at Low and Elevated Temperatures

by Bilal Khatri, Jan Rehra, Sebastian Schmeer, Ulf Breuer and Frank Balle

J. Compos. Sci. 2022, 6(3), 67; https://doi.org/10.3390/jcs6030067 - 23 Feb 2022

Cited by 7 | Viewed by 3269

Abstract

Carbon-fiber-reinforced polymers (CFRPs) are the standard lightweight composite material for structural applications in aviation. The addition of metallic fibers to CFRPs to form metal/carbon-fiber hybrid composites (MCFRPs) has been shown to improve the elastic and plastic properties and to enable a non-destructive method [...] Read more.

Carbon-fiber-reinforced polymers (CFRPs) are the standard lightweight composite material for structural applications in aviation. The addition of metallic fibers to CFRPs to form metal/carbon-fiber hybrid composites (MCFRPs) has been shown to improve the elastic and plastic properties and to enable a non-destructive method for structural health monitoring over the material’s service life. In this paper, the results from the fatigue experiments on these hybrid composites at −55, 25 and 120 °C are discussed. Multidirectional CFRP and MCFRP laminates, fabricated using the autoclave method, were tested and compared under different fatigue loading conditions, while being simultaneously monitored for temperature and electrical resistance. Magnetic phase measurements were additionally carried out for the chosen metastable austenitic steel fibers in the MCFRPs. The results show that the improved ductility of the hybrid composite due to the presence of the steel fibers leads to better performance under fatigue loads and a less-brittle failure behavior. Based on the chemical composition of the metastable austenitic steel fibers, a temperature and plastic deformation-dependent phase transformation was observed, which could potentially lead to a method for non-destructive structural health monitoring of the hybrid composite over its service life. Full article

(This article belongs to the Special Issue Metal Composites)

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13 pages, 1928 KiB

Open AccessArticle

Preparation of Gellan Gum-Inorganic Composite Film and Its Metal Ion Accumulation Property

by Masanori Yamada and Yoshihiro Kametani

J. Compos. Sci. 2022, 6(2), 42; https://doi.org/10.3390/jcs6020042 - 25 Jan 2022

Cited by 8 | Viewed by 2456

Abstract

Gellan gum is one of the water-soluble anionic polysaccharides produced by the bacteria Sphingomonas elodea. In this study, we prepared gellan gum-inorganic composite films by mixing the gellan gum and a silane coupling reagent—3-glycidoxypropyltrimethoxysilane (GPTMS). These gellan gum-GPTMS composite films were stable [...] Read more.

Gellan gum is one of the water-soluble anionic polysaccharides produced by the bacteria Sphingomonas elodea. In this study, we prepared gellan gum-inorganic composite films by mixing the gellan gum and a silane coupling reagent—3-glycidoxypropyltrimethoxysilane (GPTMS). These gellan gum-GPTMS composite films were stable in an aqueous solution and showed a thermal stability. In addition, these composite films indicated a mechanical strength by the formation of the three-dimensional network of siloxane. We demonstrated the accumulation of metal ions from a metal ion-containing aqueous solution by the composite film. As a result, although the composite film indicated the accumulation of heavy and rare-earth metal ions, the light metal ions, such as Mg(II) and Al(III) ions, did not interact with the composite material. Therefore, the accumulative mechanism of metal ions using a composite film was evaluated by IR measurements. As a consequence, although the accumulation of heavy and rare-earth metal ions occurred at both the −COO⁻ group and the −OH group in the gellan gum, the accumulation of light metal ions occurred only at the −OH group. Full article

(This article belongs to the Special Issue Metal Composites)

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11 pages, 3527 KiB

Open AccessArticle

Platinum-Decorated TiO₂: One Step Fast Monometallic Impregnation and Plasma Effect on Nanoparticles

by Rudy Trejo-Tzab, Alejandro Avila-Ortega, Patricia Quintana-Owen, Ricardo Rangel and Mayra Angélica Álvarez-Lemus

J. Compos. Sci. 2022, 6(1), 4; https://doi.org/10.3390/jcs6010004 - 24 Dec 2021

Cited by 5 | Viewed by 2743

Abstract

In the present work, N-TiO_2−x/Pt was synthesized using a homemade nitrogen plasma (AC) discharge system. The overall procedure use of low-power nitrogen plasma (100 watts) with 1 and 2 h of plasma discharge to successfully impregnate platinum nanoparticles on P25 titanium [...] Read more.

In the present work, N-TiO_2−x/Pt was synthesized using a homemade nitrogen plasma (AC) discharge system. The overall procedure use of low-power nitrogen plasma (100 watts) with 1 and 2 h of plasma discharge to successfully impregnate platinum nanoparticles on P25 titanium dioxide. The obtained samples were characterized using X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM). The results reveal the incorporation of metallic Pt up to 2.9% on the surface of TiO₂ by increasing the duration of plasma discharge by up to two hours with a constant power of 100 watts. Likewise, the incorporation of nitrogen atoms into a lattice crystal was also favored, confirming a direct relationship between the amount of Pt and nitrogen atoms introduced in TiO₂ as a function of the duration of plasma treatment. By characterizing nanoparticles loaded on a N-TiO_2−x/Pt surface, we show that joined platinum nanoparticles have two different patterns, and the boundary between these two regions coalesces. The results demonstrate that the use of nitrogen plasma to impregnate platinum nanoparticles on the surface of TiO₂ to obtain N-TiO_2−x/Pt allows wide and relevant physics and chemistry applications. Full article

(This article belongs to the Special Issue Metal Composites)

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9 pages, 3567 KiB

Open AccessArticle

Mechanical and Microstructural Response of Aluminum Composites Reinforced with Ceramic Micro-Particles

by José A. Castillo-Robles, Alicia P. Dimas-Muñoz, José A. Rodríguez-García, Carlos A. Calles-Arriaga, Eddie N. Armendáriz-Mireles, Wilian J. Pech-Rodríguez and Enrique Rocha-Rangel

J. Compos. Sci. 2021, 5(9), 228; https://doi.org/10.3390/jcs5090228 - 27 Aug 2021

Cited by 2 | Viewed by 2095

Abstract

Aluminum matrix composites have recently taken an important role in advanced applications because they have a good combination of physical and chemical properties. For this reason, in this work, aluminum composites, with additions of ceramic particles (mullite or tungsten carbide), were manufactured in [...] Read more.

Aluminum matrix composites have recently taken an important role in advanced applications because they have a good combination of physical and chemical properties. For this reason, in this work, aluminum composites, with additions of ceramic particles (mullite or tungsten carbide), were manufactured in order to determine the effect of those particles on the mechanical properties and microstructure of aluminum. The manufacture of the composites was carried out by means of powder metallurgy. We studied composites with additions of 0.5 and 1 vol.% of the respective ceramic. Composites were sintered at 580 and 601 °C, which corresponds to 88 and 91% of the melting point of aluminum, respectively. Observations in SEM, together with EDX analysis, confirm that mullite particles are located at intragranular and transgranular positions of the aluminum matrix, while tungsten carbide particles were found mostly at intragranular areas of the matrix. From the analysis of the studied ceramics, it was found that with the use of mullite, there are greater improvements in the hardness and elastic modulus of the manufactured composite. Full article

(This article belongs to the Special Issue Metal Composites)

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13 pages, 3636 KiB

Open AccessArticle

Investigation of the Deformation Behaviour and Resulting Ply Thicknesses of Multilayered Fibre–Metal Laminates

by Missam Irani, Moritz Kuhtz, Mathias Zapf, Madlen Ullmann, Andreas Hornig, Maik Gude and Ulrich Prahl

J. Compos. Sci. 2021, 5(7), 176; https://doi.org/10.3390/jcs5070176 - 6 Jul 2021

Cited by 7 | Viewed by 2765

Abstract

Multilayered fibre–metal laminates (FMLs) are composed of metal semifinished products and fibre-reinforced plastics, and benefit from the advantages of both material classes. Light metals in combination with fibre-reinforced thermoplastics are highly suitable for mass production of lightweight structures with good mechanical properties. As [...] Read more.

Multilayered fibre–metal laminates (FMLs) are composed of metal semifinished products and fibre-reinforced plastics, and benefit from the advantages of both material classes. Light metals in combination with fibre-reinforced thermoplastics are highly suitable for mass production of lightweight structures with good mechanical properties. As the formability of light metal sheets is sometimes limited at room temperature, increasing the process temperature is an appropriate approach to improve formability. However, the melting of thermoplastic materials and resulting loss of stiffness limit the processing temperature. Since single-ply layers have different through-thickness stiffnesses, the forming process changes the ply thickness of the multilayered laminate. In the present study, the deformation behaviour of multilayered FMLs was investigated using a two-dimensional finite-element model assuming plane strain. The thermoelastic-plastic finite-element analysis made investigation of the variation in thickness made possible by incorporating sufficient mesh layers in the thickness direction. The results indicate that a thermoelastic-plastic finite-element model can predict the delamination of plies during deformation, as well as in the final product. Additionally, the predicted changes in thickness of the plies are in good agreement with experimental results when a temperature-dependent friction coefficient is used. Full article

(This article belongs to the Special Issue Metal Composites)

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27 pages, 18058 KiB

Open AccessArticle

Preliminary Experimental and Numerical Study of Metal Element with Notches Reinforced by Composite Materials

by Paweł J. Romanowicz, Bogdan Szybiński and Mateusz Wygoda

J. Compos. Sci. 2021, 5(5), 134; https://doi.org/10.3390/jcs5050134 - 18 May 2021

Cited by 6 | Viewed by 2447

Abstract

The presented study is related to the application of the composite overlays used in order to decrease the effect of the stress concentrations around the cut-outs in structural metal elements. The proposed approach with the application of the digital image correlation extends the [...] Read more.

The presented study is related to the application of the composite overlays used in order to decrease the effect of the stress concentrations around the cut-outs in structural metal elements. The proposed approach with the application of the digital image correlation extends the recently presented studies. Such structural elements with openings of various shapes have been accommodated for a wide range of industrial applications. These structures exhibit certain stress concentrations which decrease their durability and strength. To restore their strength, various reinforcing overlays can be used. In the present paper, the flat panel structure without and with the composite overlays made of HEXCEL TVR 380 M12/26%/R-glass/epoxy is under the experimental and the numerical study. Particular attention is paid to the investigation of the samples with the rectangular holes, which for smooth rounded corners offer a higher durability than the samples with the circular hole of the same size. The experimental results are obtained for the bare element and are reinforced with composite overlay samples. The experimental results are obtained with the use of the Digital Image Correlation method, while the numerical results are the product of the Finite Element Analysis. In the numerical analysis, the study of the shape, size and fiber orientation in applied overlays is done. The reduction of the stress concentration observed in opening notches has confirmed the effectiveness of the overlay application. In the investigated example, the application of the square composite overlay increased the structure strength even by 25%. Full article

(This article belongs to the Special Issue Metal Composites)

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19 pages, 4853 KiB

Open AccessArticle

Experimental Design of Solid Particle Wear Behavior of Ni-Based Composite Coatings

by Pragyan Senapati, Harekrushna Sutar, Rabiranjan Murmu and Shubhra Bajpai

J. Compos. Sci. 2021, 5(5), 133; https://doi.org/10.3390/jcs5050133 - 17 May 2021

Cited by 5 | Viewed by 2400

Abstract

The composition of nickel-based metal matrix NiCrBSi was varied with 5%, 10% and 15% of Al₂O₃ particles to obtain high wear resistant coatings by means of a high-velocity oxy fuel (HVOF) thermal spraying process. The coating was characterized by optical [...] Read more.

The composition of nickel-based metal matrix NiCrBSi was varied with 5%, 10% and 15% of Al₂O₃ particles to obtain high wear resistant coatings by means of a high-velocity oxy fuel (HVOF) thermal spraying process. The coating was characterized by optical microscope, scanning electron microscope (SEM) and X-ray diffractometer (XRD). The physical properties of coatings such as porosity, thickness, surface roughness, surface hardness, fracture toughness, bond strength and density were measured and compared. The experimental design of Taguchi L27 orthogonal array was employed to study and compare the effect of parameters such as impingement angle, impact velocity and alumina per cent in the coating on erosion. The coating containing 15 wt.% of Al₂O₃ and erodent speed of 33 m/s striking at inclination angle of 30° proved to be the best arrangement in preventing volume loss to a minimum of 0.00015 cc due to low-impact energy, high bond strength and high surface hardness. Analysis of variance (ANOVA) supported the assertion that the impact angle (A) of erodent and composition (C) were the factors contributing most to the volumetric loss as indicated by their combined effect A × C leading to the highest combined factor of 7.34. The scanning electron microscopy (SEM) images of the eroded coatings reveal that the mechanisms of erosion were the fracturing of splats, development of craters, micro cutting and ploughing action. Full article

(This article belongs to the Special Issue Metal Composites)

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9 pages, 7016 KiB

Open AccessArticle

Investigating the Hall-Petch Constants for As-Cast and Aged AZ61/CNTs Metal Matrix Composites and Their Role on Superposition Law Exponent

by Aqeel Abbas and Song-Jeng Huang

J. Compos. Sci. 2021, 5(4), 103; https://doi.org/10.3390/jcs5040103 - 9 Apr 2021

Cited by 13 | Viewed by 2343

Abstract

AZ61/carbon nanotubes (CNTs) (0, 0.1, 0.5, and 1 wt.%) composites were successfully fabricated by using the stir-casting method. Hall–Petch relationship and superposition of different strengthening mechanisms were analyzed for aged and as-cast AZ61/CNTs composites. Aged composites showed higher frictional stress (108.81 MPa) than [...] Read more.

AZ61/carbon nanotubes (CNTs) (0, 0.1, 0.5, and 1 wt.%) composites were successfully fabricated by using the stir-casting method. Hall–Petch relationship and superposition of different strengthening mechanisms were analyzed for aged and as-cast AZ61/CNTs composites. Aged composites showed higher frictional stress (108.81 MPa) than that of as-cast (31.56 Mpa) composites when the grain size was fitted directly against the experimentally measured yield strength. In contrast, considering the superposition of all contributing strengthening mechanisms, the Hall–Petch constants contributed by only grain-size strengthening were found (σ₀ = 100.06 Mpa and K_f = 0.3048 Mpa m^1/2) for as-cast and (σ₀ = 87.154 Mpa and K_f = 0.3407 Mpa m^1/2) for aged composites when superposition law exponent is unity. The dislocation density for the as-cast composites was maximum (8.3239 × 1013 m⁻²) in the case of the AZ61/0.5 wt.%CNT composite, and for aged composites, it increased with the increase in CNTs concentration and reached the maximum value (1.0518 × 1014 m⁻²) in the case of the AZ61/1 wt.%CNT composite. Full article

(This article belongs to the Special Issue Metal Composites)

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19 pages, 11136 KiB

Open AccessArticle

Determination and Validation of Residual Stresses in CFRP/Metal Hybrid Components Using the Incremental Hole Drilling Method

by Tao Wu, Steffen R. Tinkloh, Thomas Tröster, Wolfgang Zinn and Thomas Niendorf

J. Compos. Sci. 2020, 4(3), 143; https://doi.org/10.3390/jcs4030143 - 21 Sep 2020

Cited by 14 | Viewed by 3562

Abstract

Lightweight materials contribute to an efficient decrease in fuel consumption in the automotive and aircraft industries. Hybrid components made of metal and carbon fiber-reinforced plastics (CFRP) have a high potential in lightweight applications due to their high strength-to-weight ratio. For cost-effective processing of [...] Read more.

Lightweight materials contribute to an efficient decrease in fuel consumption in the automotive and aircraft industries. Hybrid components made of metal and carbon fiber-reinforced plastics (CFRP) have a high potential in lightweight applications due to their high strength-to-weight ratio. For cost-effective processing of hybrid materials, advanced manufacturing processes such as the prepreg-press-technology have been developed, in which the bonding between a metallic component and a fiber compound is exclusively realized in the forming process. However, upon processing of these hybrid components at elevated temperature, the difference in thermal expansion coefficients of the two materials leads to the formation of tensile residual stresses upon cooling. It is well known that these tensile residual stresses can be detrimentally effective with respect to the durability of a hybrid component. The objective of this work is to accurately measure and analyze residual stresses in hybrid components made of unidirectional CFRP and steel through the incremental hole drilling method. Within this study, the evaluation formalism for orthotropic materials is employed for measuring non-uniform residual stresses in hybrid materials. In order to improve the measurement accuracy, a customized strain gauge with eight grids is employed and a drilling increment size of only 20 µm is utilized. The influence of the angle between the strain gauge rosette and the fiber direction on the evaluation of the residual stresses is investigated. In order to evaluate the reliability of the results determined, a bending test applying a well-defined load is carried out. By direct comparison of the experimentally determined stresses and stress values calculated by the finite element method, the applicability of the hole drilling method for robust determination of residual stresses in CFRP/metal hybrid components is finally validated. Full article

(This article belongs to the Special Issue Metal Composites)

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14 pages, 5110 KiB

Open AccessArticle

A Nonlinear Analysis Interpretation of Off-Axis Test Results in Metal Matrix Composites

by Jalees Ahmad, Unni Santhosh and Swamy Chandu

J. Compos. Sci. 2020, 4(3), 127; https://doi.org/10.3390/jcs4030127 - 31 Aug 2020

Cited by 1 | Viewed by 2449

Abstract

A unit-cell based micromechanics approach is used to perform nonlinear finite element analyses of off-axis tensile tests on an SCS-6/Ti-6Al-4V composite. The results are used in predicting the global deformation response of the composite that includes the effect of fiber-matrix interface damage. The [...] Read more.

A unit-cell based micromechanics approach is used to perform nonlinear finite element analyses of off-axis tensile tests on an SCS-6/Ti-6Al-4V composite. The results are used in predicting the global deformation response of the composite that includes the effect of fiber-matrix interface damage. The predictions are compared with laboratory test data of uniaxial off-axis specimens. Based on the comparison, it is found that the procedure effectively predicts global composite response with reasonable accuracy under a general multiaxial stress state. Full article

(This article belongs to the Special Issue Metal Composites)

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16 pages, 3863 KiB

Open AccessArticle

Synthesis of Supported Metal Nanoparticles (Au/TiO₂) by the Suspension Impregnation Method

by Carolina Rodríguez-Martínez, Ángel Emilio García-Domínguez, Fernando Guerrero-Robles, Rafael Omar Saavedra-Díaz, Gilberto Torres-Torres, Carlos Felipe, Reyna Ojeda-López, Adib Silahua-Pavón and Adrián Cervantes-Uribe

J. Compos. Sci. 2020, 4(3), 89; https://doi.org/10.3390/jcs4030089 - 9 Jul 2020

Cited by 17 | Viewed by 4811

Abstract

This work reports a new technique called “Suspension Impregnation Method” (SiM) as an alternative to the “Incipient Impregnation Method” (IiM) for the synthesis of noble metal (Au) nanoparticles. The SiM was used to synthesize gold nanoparticles supported by titanium oxide and compared with [...] Read more.

This work reports a new technique called “Suspension Impregnation Method” (SiM) as an alternative to the “Incipient Impregnation Method” (IiM) for the synthesis of noble metal (Au) nanoparticles. The SiM was used to synthesize gold nanoparticles supported by titanium oxide and compared with those of IiM. The reactor for the SiM technique was based on the principles of mixing, heat, and mass transfer of the suspension reactors and the metal particle synthesis was processed in situ under the oxidation reduction potentials. Three different conditions were established to observe the effect of pH on the size of the metal particles: acid (HCl), neutral (water) and alkaline (urea). The samples were characterized by nitrogen adsorption, X-Ray Diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Thermogravimetric Analysis (TGA)/Differential Thermal Analysis (DTA), Transmission Electron Microscopy (TEM) and CO₂ adsorption. The surface area was slightly modified, and the average pore diameter was reduced in all materials. The structure of the titanium oxide was not altered. A deposit of organic material was detected in samples synthesized in alkaline medium for both methods. The pH influenced the formation of conglomerates in IiM and resulted in large particle sizes (3–9 nm). In contrast, an in situ reduction in the species in SiM resulted in smaller particle sizes than IiM (2–3 nm). Full article

(This article belongs to the Special Issue Metal Composites)

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18 pages, 6079 KiB

Open AccessArticle

Synthesis of Hematite Nanodiscs from Natural Laterites and Investigating Their Adsorption Capability of Removing Ni²⁺ and Cd²⁺ Ions from Aqueous Solutions

by B. P. N. Gunawardhana, C. A. Gunathilake, K. E. D. Y. T. Dayananda, D. M. S. N. Dissanayake, M. M. M. G. P. G. Mantilaka, C. S. Kalpage, R. M. L. D. Rathnayake, R. M. G. Rajapakse, A. S. Manchanda, Thusitha N. B. Etampawala, B. G. N. D. Weerasekara, P. N. K. Fernando and Rohan S. Dassanayake

J. Compos. Sci. 2020, 4(2), 57; https://doi.org/10.3390/jcs4020057 - 20 May 2020

Cited by 18 | Viewed by 3919

Abstract

In this work, disc-like hematite (Fe₂O₃) nanoparticles were prepared using a readily available inexpensive earth material, ferruginous laterite, via a low-cost synthesis route. Prepared hematite nanoparticles were characterized using X-Ray diffraction (XRD), inductively coupled plasma mass spectroscopy (ICP-MS), particle [...] Read more.

In this work, disc-like hematite (Fe₂O₃) nanoparticles were prepared using a readily available inexpensive earth material, ferruginous laterite, via a low-cost synthesis route. Prepared hematite nanoparticles were characterized using X-Ray diffraction (XRD), inductively coupled plasma mass spectroscopy (ICP-MS), particle size analyzer (PSA), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and nitrogen adsorption-desorption analyzer. The performance of hematite nanoparticles was evaluated as a heavy metal ion adsorbent. Batch adsorption experiments were conducted to study the adsorption behaviour of Ni²⁺ and Cd²⁺ ions as a function of the amount of adsorbent, contact time, and pH. Adsorption data fitted to the linearized Langmuir and Freundlich kinetic models were compared and discussed. The correlation coefficient (R²) was used to determine the best fit kinetic model. Our data fitted the Langmuir kinetic model well and the highest adsorption efficiencies were found to be 62.5 mg/g for Ni²⁺ and 200 mg/g for Cd²⁺, respectively. Due to high surface area, pore volume with active sites, and sorption capabilities, hematite nanoparticles can be used as efficient and economical nano-adsorbents for the removal of Ni²⁺ and Cd²⁺ ions from industrial wastewater. Full article

(This article belongs to the Special Issue Metal Composites)

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13 pages, 2520 KiB

Open AccessArticle

A Novel Design and Performance Results of An Electrically Tunable Piezoelectric Vibration Energy Harvester (TPVEH)

by Sreekumari Raghavan and Rishi Gupta

J. Compos. Sci. 2020, 4(2), 39; https://doi.org/10.3390/jcs4020039 - 19 Apr 2020

Cited by 6 | Viewed by 2455

Abstract

The need for energy harvesters for various applications, including structural health monitoring (SHM) in remote and inaccessible areas, is well established. Energy harvesters can utilize the ambient vibration of the body on which they are mounted to generate energy, thus eliminating the need [...] Read more.

The need for energy harvesters for various applications, including structural health monitoring (SHM) in remote and inaccessible areas, is well established. Energy harvesters can utilize the ambient vibration of the body on which they are mounted to generate energy, thus eliminating the need for an external source of power. One such type of harvester is designed using piezoelectric materials and using a cantilever type set-up. However, the challenge associated with cantilever-based Piezoelectric Vibration Energy Harvesters (PVEH) is that its output power reduces when the ambient vibration frequency deviates from the resonant frequency of the harvester. This calls for a mechanism to tune its resonant frequency to match with the ambient frequency. This article presents an innovative design of an electrically tunable PVEH. The PVEH is integrated with an Ionic Polymer Metal Composite (IPMC) as an actuator that loads the cantilever beam, changing the stiffness of the beam. IPMC utilizes low power, and the authors demonstrate in this paper that a net gain of power can be achieved by this novel design. For the configuration used, it is experimentally proven that a frequency shift from 5.9 Hz to 8 Hz is achieved with three actuation values. Typical power output from the harvester is 52.03 µW when the power spent on actuation is only 0.765 µW. On-going modeling of this system using simulation software is expected to lead to further optimization and prototyping of design. Full article

(This article belongs to the Special Issue Metal Composites)

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Review

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19 pages, 5709 KiB

Open AccessReview

Incremental Sheet Forming of Metal-Based Composites Used in Aviation and Automotive Applications

by Tomasz Trzepieciński, Sherwan Mohammed Najm, Tomaž Pepelnjak, Kamel Bensaid and Marcin Szpunar

J. Compos. Sci. 2022, 6(10), 295; https://doi.org/10.3390/jcs6100295 - 9 Oct 2022

Cited by 10 | Viewed by 3271

Abstract

For several years, the aviation industry has seen dynamic growth in the use of composite materials due to their low weight and high stiffness. Composites are being considered as a means of building lighter, safer, and more fuel-efficient automobiles. Composite materials are the [...] Read more.

For several years, the aviation industry has seen dynamic growth in the use of composite materials due to their low weight and high stiffness. Composites are being considered as a means of building lighter, safer, and more fuel-efficient automobiles. Composite materials are the building material of a relatively new kind of unmanned aerial vehicle, commonly known as a drone. Incremental forming methods allow materials to be quickly formed without the need to manufacture conventional metal dies. Their advantage is the high profitability during the production of prototypes and a small series of products when compared with the conventional methods of plastic forming. This article provides an overview of the incremental forming capabilities of the more commonly produced aluminium- and titanium-based laminates, which are widely used in the aircraft industry. In addition, for composites that are not currently incrementally formed, i.e., aramid-reinforced aluminium laminates, the advantages and potential for incremental forming are presented. Full article

(This article belongs to the Special Issue Metal Composites)

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52 pages, 17200 KiB

Open AccessEditor’s ChoiceReview

New Advances and Future Possibilities in Forming Technology of Hybrid Metal–Polymer Composites Used in Aerospace Applications

by Tomasz Trzepieciński, Sherwan Mohammed Najm, Manel Sbayti, Hedi Belhadjsalah, Marcin Szpunar and Hirpa G. Lemu

J. Compos. Sci. 2021, 5(8), 217; https://doi.org/10.3390/jcs5080217 - 13 Aug 2021

Cited by 66 | Viewed by 11337

Abstract

Fibre metal laminates, hybrid composite materials built up from interlaced layers of thin metals and fibre reinforced adhesives, are future-proof materials used in the production of passenger aircraft, yachts, sailplanes, racing cars, and sports equipment. The most commercially available fibre–metal laminates are carbon [...] Read more.

Fibre metal laminates, hybrid composite materials built up from interlaced layers of thin metals and fibre reinforced adhesives, are future-proof materials used in the production of passenger aircraft, yachts, sailplanes, racing cars, and sports equipment. The most commercially available fibre–metal laminates are carbon reinforced aluminium laminates, aramid reinforced aluminium laminates, and glass reinforced aluminium laminates. This review emphasises the developing technologies for forming hybrid metal–polymer composites (HMPC). New advances and future possibilities in the forming technology for this group of materials is discussed. A brief classification of the currently available types of FMLs and details of their methods of fabrication are also presented. Particular emphasis was placed on the methods of shaping FMLs using plastic working techniques, i.e., incremental sheet forming, shot peening forming, press brake bending, electro-magnetic forming, hydroforming, and stamping. Current progress and the future directions of research on HMPCs are summarised and presented. Full article

(This article belongs to the Special Issue Metal Composites)

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Other

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6 pages, 1126 KiB

Open AccessBrief Report

Magnetic Behavior of an Iron Gluconate/Polyaniline Composite

by Yusuke Koshikawa and Hiromasa Goto

J. Compos. Sci. 2021, 5(9), 252; https://doi.org/10.3390/jcs5090252 - 19 Sep 2021

Cited by 2 | Viewed by 2017

Abstract

Oxidative polymerization conducted the synthesis of polyaniline in the presence of iron gluconate in the water. Iron gluconate is present in the resulting polyaniline (PANI). The PANI composite exhibited multiple signals in electron spin resonance, including half-field resonance of multiple spin states, the [...] Read more.

Oxidative polymerization conducted the synthesis of polyaniline in the presence of iron gluconate in the water. Iron gluconate is present in the resulting polyaniline (PANI). The PANI composite exhibited multiple signals in electron spin resonance, including half-field resonance of multiple spin states, the center-field resonance of polarons as radical cations in conducting polymer, and a signal from a defect in the main chain. Infrared (IR) absorption spectroscopy measurements confirmed the chemical structure of the PANI composite. The composite exhibits the mixed magnetism of PANI as a conducting polymer and Fe ions in the composite according to superconducting interference device (SQUID) measurements. Combining organic-conjugated polymers and inorganic materials can result in a unique magnetism. Full article

(This article belongs to the Special Issue Metal Composites)

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