Materials

2023

Jump to: 2022, 2021, 2020

14 pages, 7577 KiB

Open AccessArticle

Hot Deformation Behavior and Mechanisms of SiC Particle Reinforced Al-Zn-Mg-Cu Alloy Matrix Composites

by Enze Diao, Jianzhong Fan, Zhiyu Yang, Zhaochong Lv, Hao Gao and Junhui Nie

Materials 2023, 16(23), 7430; https://doi.org/10.3390/ma16237430 - 29 Nov 2023

Cited by 2 | Viewed by 1006

Abstract

A systematic and comprehensive analysis of the hot deformation and mechanisms of SiC particle-reinforced aluminum matrix composites is significant for optimizing the processing of the composites and obtaining the desired components. Based on this, related research on 11 vol% SiCp particle-reinforced 7050Al matrix [...] Read more.

A systematic and comprehensive analysis of the hot deformation and mechanisms of SiC particle-reinforced aluminum matrix composites is significant for optimizing the processing of the composites and obtaining the desired components. Based on this, related research on 11 vol% SiCp particle-reinforced 7050Al matrix composites was carried out. Hot compression experiments were carried out on the Gleeble-3500 thermal simulator to study the hot deformation behavior of composites at the temperature of 370–520 °C and strain rate of 0.001–10 s⁻¹. The hyperbolic sine constitutive equation of the material was established, and the processing map was calculated. Combining the typical metallograph and misorientation angle distribution, the microstructure evolution mechanism of composites was analyzed, and the effect of particles on recrystallization behavior was investigated. Under certain process conditions, the dominant deformation mechanism of composites changed from dynamic recovery (DRV) to dynamic recrystallization (DRX), and the grain boundary sliding mechanism began to play a role. In addition, high temperature tensile and elongation at break were tested, and it was found that the dominant form of fracture failure changed from brittle fracture of the particles to ductile fracture of the matrix as the temperature increased. Full article

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19 pages, 8541 KiB

Open AccessEditor’s ChoiceReview

3D Textiles Based on Warp Knitted Fabrics: A Review

by Lars Hahn, Konrad Zierold, Anke Golla, Danny Friese and Steffen Rittner

Materials 2023, 16(10), 3680; https://doi.org/10.3390/ma16103680 - 11 May 2023

Cited by 10 | Viewed by 6387

Abstract

Fibre-reinforced composites (FRCs) are already well established in several industrial sectors such as aerospace, automotive, plant engineering, shipbuilding and construction. The technical advantages of FRCs over metallic materials are well researched and proven. The key factors for an even wider industrial application of [...] Read more.

Fibre-reinforced composites (FRCs) are already well established in several industrial sectors such as aerospace, automotive, plant engineering, shipbuilding and construction. The technical advantages of FRCs over metallic materials are well researched and proven. The key factors for an even wider industrial application of FRCs are the maximisation of resource and cost efficiency in the production and processing of the textile reinforcement materials. Due to its technology, warp knitting is the most productive and therefore cost-effective textile manufacturing process. In order to produce resource-efficient textile structures with these technologies, a high degree of prefabrication is required. This reduces costs by reducing the number of ply stacks, and by reducing the number of extra operations through final path and geometric yarn orientation of the preforms. It also reduces waste in post-processing. Furthermore, a high degree of prefabrication through functionalisation offers the potential to extend the application range of textile structures as purely mechanical reinforcements by integrating additional functions. So far, there is a gap in terms of an overview of the current state-of-the-art of relevant textile processes and products, which this work aims to fill. The focus of this work is therefore to provide an overview of warp knitted 3D structures. Full article

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18 pages, 9551 KiB

Open AccessArticle

Investigation of the Tribological Behaviour of Various AMC Surfaces against Brake Lining Material

by Sarah Johanna Hirsch, Patrick Eiselt, Ismail Ozdemir, Thomas Grund, Andreas Nestler, Thomas Lampke and Andreas Schubert

Materials 2023, 16(3), 1001; https://doi.org/10.3390/ma16031001 - 21 Jan 2023

Cited by 4 | Viewed by 1724

Abstract

AlSi7Mg/SiC_p aluminium matrix composites (AMCs) with a high ceramic content (35 vol.%) that were produced by using the field-assisted sintering technique (FAST) were subjected to tribological preconditioning and evaluated as a potential lightweight material to substitute grey cast iron brake discs. However, [...] Read more.

AlSi7Mg/SiC_p aluminium matrix composites (AMCs) with a high ceramic content (35 vol.%) that were produced by using the field-assisted sintering technique (FAST) were subjected to tribological preconditioning and evaluated as a potential lightweight material to substitute grey cast iron brake discs. However, since an uncontrolled running-in process of the AMC surface can lead to severe wear and thus to failure of the friction system, AMC surfaces cannot be used directly after finishing and have to be preconditioned. A defined generation of a tribologically conditioned surface (tribosurface) is necessary, as was the aim in this study. To simulate tribological conditions in automotive brake systems, the prepared AMC samples were tested in a pin-on-disc configuration against conventional brake lining material under dry sliding conditions. The influence of the surface topography generated by face turning using different indexable inserts and feeds or an additional plasma electrolytic treatment was investigated at varied test pressures and sliding distances. The results showed that the coefficient of friction remained nearly constant when the set pressure was reached, whereas the initial topography of the samples studied by SEM varied substantially. A novel approach based on analysing the material ratio determined by 3D surface measurement was developed in order to obtain quantitative findings for industrial application. Full article

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2022

Jump to: 2023, 2021, 2020

14 pages, 3829 KiB

Open AccessArticle

Loading Rate and Temperature Interaction Effects on the Mode I Fracture Response of a Ductile Polyurethane Adhesive Used in the Automotive Industry

by Mael Perez, Alireza Akhavan-Safar, Ricardo J. C. Carbas, Eduardo A. S. Marques, Sabine Wenig and Lucas F. M. da Silva

Materials 2022, 15(24), 8948; https://doi.org/10.3390/ma15248948 - 14 Dec 2022

Cited by 14 | Viewed by 2669

Abstract

Due to their high elongation at failure and damping capacity, polyurethanes are one of the main types of adhesives used in automotive structures. However, despite the wide range of applications of adhesives, their fracture mechanics behavior is still poorly studied in the literature, [...] Read more.

Due to their high elongation at failure and damping capacity, polyurethanes are one of the main types of adhesives used in automotive structures. However, despite the wide range of applications of adhesives, their fracture mechanics behavior is still poorly studied in the literature, especially when both the loading rate and ambient temperature change. Accordingly, the main aim of the current work is to deal with the research gap. In the current research, mode I fracture energy of a ductile polyurethane adhesive with adaptive properties for its industrial application is determined at different test speeds and temperatures. Tests were done at quasi-static, intermediate, and high-speed levels and each at three different temperatures, including low, high, and room temperature. Mode I fracture toughness was determined using DCB tests. Increasing the loading rate from quasi-static to 6000 mm/min was found to significantly increase the maximum strength of the tested DCBs (from 1770 N to about 4180 N). The greatest sensitivity to the loading rate was observed for the DCBs tested at room temperature, where the fracture energy increased by a factor of 3.5 from quasi-static (0.2 mm/min) to a high loading rate (6000 mm/min). The stiffness analysis of the DCB samples showed that the transition from below the T_g to room temperature decreases the bond stiffness by about 60%, while a further temperature increase (from 23 °C to 60 °C) has no significant effect on this parameter. Since polyurethane-bonded joints often experience a wide range of temperatures and loading rates in service, the obtained results can be used to design these joints more securely against such loading/environmental conditions. Full article

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13 pages, 7606 KiB

Open AccessArticle

Microstructure and Mechanical Properties of Hybrid AZ91 Magnesium Matrix Composite with Ti and SiC Particles

by Katarzyna N. Braszczyńska-Malik

Materials 2022, 15(18), 6301; https://doi.org/10.3390/ma15186301 - 10 Sep 2022

Cited by 8 | Viewed by 2253

Abstract

In this paper, a new hybrid metal matrix composite, named AZ91/(SiC + Ti)_p, is presented. The commercial AZ91 magnesium alloy was chosen as the matrix. The composite was reinforced with both SiC and Ti particles. The investigated material was successfully fabricated [...] Read more.

In this paper, a new hybrid metal matrix composite, named AZ91/(SiC + Ti)_p, is presented. The commercial AZ91 magnesium alloy was chosen as the matrix. The composite was reinforced with both SiC and Ti particles. The investigated material was successfully fabricated using stir casting methods. Microstructure analyses were carried out by digital and scanning electron microscopy with an energy-dispersive X-ray spectrometer (SEM + EDX). Detailed investigations disclosed the presence (besides the reinforced particles) of primary dendrites of the α phase, α + γ eutectic and some part of discontinuous precipitates of the γ phase in the composite microstructure. The composite was characterised by uniform distribution of the Ti particles, whereas the SiC particles were revealed inside the primary dendrites of the α phase, on the Ti particles and in the interdendritic regions as a mixture with the α + γ eutectic. Both the tensile and compression strength as well as the yield strength of the composite were examined in both uniaxial tensile and compression tests at room temperature. The fabricated AZ91/(SiC + Ti)_p hybrid composite exhibited higher mechanical properties of all those investigated in comparison with the unreinforced AZ91 matrix alloy (cast in the same conditions). Additionally, analyses of the fracture surfaces of the AZ91/(SiC + Ti)_p hybrid composite carried out using scanning electron microscopy (SEM + EDX) were presented. Full article

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12 pages, 10793 KiB

Open AccessArticle

The Effect of Different Nanomaterials Additions in Clay-Based Composites on Electromagnetic Transmission

by Ivan Vrdoljak, Jelena Brdarić, Slavko Rupčić, Berislav Marković, Ivana Miličević, Vanja Mandrić, Damir Varevac, Dalibor Tatar, Nikolina Filipović, Imre Szenti and Ákos Kukovecz

Materials 2022, 15(15), 5115; https://doi.org/10.3390/ma15155115 - 22 Jul 2022

Cited by 2 | Viewed by 1916

Abstract

In this study, clay composites were subjected to electromagnetic transmission testing at frequencies in the region of non-ionizing radiation. Specimens were made with partial substitution of clay with different admixtures by mass. Admixtures used were Fly Ash, four different particle sizes and phases [...] Read more.

In this study, clay composites were subjected to electromagnetic transmission testing at frequencies in the region of non-ionizing radiation. Specimens were made with partial substitution of clay with different admixtures by mass. Admixtures used were Fly Ash, four different particle sizes and phases of Titanium Dioxide (TiO₂), Zinc Ferrite (ZnFe₂O₄), Maghemite (γ-Fe₂O₃) and Antimony Tin Oxide (ATO). The additives were thoroughly (chemically, structurally, morphologically) characterized. The replacement percentage was 5 wt.%. Electromagnetic transmission assessment included S₂₁ transmission coefficient measurements for samples with different additives. The lowest transmission was reported for the clay specimens with ATO and Titanium Dioxide, especially at higher frequencies. A decrease in the transmission parameter with increasing specimen thickness was also confirmed. Full article

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19 pages, 5049 KiB

Open AccessArticle

Analytical Model of Piezoresistivity for an Inner-Adhesive-Type Carbon Fibre Reinforced Plastic Tunnel Reinforcement

by Hongbin Nie, Shuancheng Gu and Hongmei Mao

Materials 2022, 15(13), 4602; https://doi.org/10.3390/ma15134602 - 30 Jun 2022

Cited by 1 | Viewed by 2000

Abstract

Cracks in a tunnel lining often emerge under the coupling action of earth and water pressures in a complex stratum environment, and accidents often occur in the process of repairing cracks. In this study, we used the force-sensitive properties of embedded carbon fibre [...] Read more.

Cracks in a tunnel lining often emerge under the coupling action of earth and water pressures in a complex stratum environment, and accidents often occur in the process of repairing cracks. In this study, we used the force-sensitive properties of embedded carbon fibre to conduct early-warning research on lining reinforcement to prevent secondary damage during tunnel lining reinforcement. According to the earth load characteristics, a bond stress–slip model of the embedded carbon fibre under bidirectional earth pressure was established on the basis of the thick-walled cylinder theory and the semi-inverse method in elastic theory. The length change of a single fibre was obtained on the basis of the principle that the volume of a single carbon fibre is constant during the deformation process. The resistance and strain model of the single carbon fibre under the action of an external force was then established following the relationship between the resistance, the length change and the volume change of the single carbon fibre. The resistance of carbon fibre composite materials, according to their production technology and unidirectional force properties, was assumed to be a mixture of the series and parallel resistances of the single carbon fibre, and a piezoresistive model of carbon fibre composite materials was formed by using the multidimensional Taylor series expansion and the idea of the average equivalent. The comparison between the theoretical and monitoring values of the piezoresistive model in a tunnel project in Tibet, China revealed that the resistance of various types of carbon fibres increases with the radius of the lining reinforcement and earth pressure and decreases with an increase in the lining reinforcement thickness. Meanwhile, the angles at different positions of the lining reinforcement also have certain effects on the resistance value of the carbon fibre. The variation curve of the piezoresistive model was exponential in both deeply and shallowly buried tunnels, which verifies the rationality of the model. Full article

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2021

Jump to: 2023, 2022, 2020

15 pages, 5016 KiB

Open AccessArticle

Fast and Clean Synthesis of Nylon-6/Synthetic Saponite Nanocomposites

by Alejandro Madrid, Elena Pérez, Miguel Ángel Vicente, Vicente Rives and Raquel Trujillano

Materials 2022, 15(1), 163; https://doi.org/10.3390/ma15010163 - 27 Dec 2021

Cited by 3 | Viewed by 2344

Abstract

Nylon/saponite nanocomposites were synthesized and characterized. The nanocomposites were prepared by means of a fast, efficient, low cost, and environmentally friendly method. All of the tested preparations resulted in the pre-designed nanocomposites. To this end, delaminated saponites were directly synthesized to be used [...] Read more.

Nylon/saponite nanocomposites were synthesized and characterized. The nanocomposites were prepared by means of a fast, efficient, low cost, and environmentally friendly method. All of the tested preparations resulted in the pre-designed nanocomposites. To this end, delaminated saponites were directly synthesized to be used as a filler in a polymer matrix formed by nylon-6 by the in situ intercalation polymerisation of an ε-caprolactam monomer without the use of surfactants or other organic reagents to organophilise the clay, thus avoiding the drawbacks of contamination. The efficiency of the preparation method increased, and significant savings were achieved in terms of both energy reaction time, savings of 60% and 70%, respectively, by using microwave radiation as an energy source during the synthesis of the nanocomposites. In addition, given that the method that was followed avoids the use of contaminating organophilic agents, it is important to highlight the savings in reagents and the fact that there was zero environmental contamination. Full article

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27 pages, 12069 KiB

Open AccessArticle

Experimental Study of the Impact of Glass Beads on Adhesive Joint Strength and Its Failure Mechanism

by João P. J. R. Santos, Eduardo A. S. Marques, Ricardo J. C. Carbas, Frida Gilbert and Lucas F. M. da Silva

Materials 2021, 14(22), 7013; https://doi.org/10.3390/ma14227013 - 19 Nov 2021

Cited by 4 | Viewed by 2815

Abstract

The use of modern structural adhesives provides a lightweight, practical, and high strength joining methodology, which is increasingly being adopted in the automotive and aeronautical sectors, among many others. However, the strict mechanical performance standards that must be met in these applications require [...] Read more.

The use of modern structural adhesives provides a lightweight, practical, and high strength joining methodology, which is increasingly being adopted in the automotive and aeronautical sectors, among many others. However, the strict mechanical performance standards that must be met in these applications require a constant search for ways of improving the adhesives’ behavior, which has led to the growing use of reinforcements as a way of improving the capabilities of bonded joints. The aim of this work was, thus, to analyze how the addition of inorganic fillers to the adhesive layer affects a joint’s strength and its failure mechanism. To this end, single lap joint specimens with mild steel and high strength steel substrates were tested, at quasi-static speeds, and with different amounts of glass microspheres reinforcing two different structural adhesives. The experimental results indicated that the addition of glass particles reduced the joint performance for both substrates under study. Furthermore, the failure pattern was found to evolve from adhesive failure to a cohesive type of failure as the amount of glass particles present in the adhesive was increased. Full article

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14 pages, 4857 KiB

Open AccessArticle

On the Structure and Properties of AlMgB₁₄-TiB₂ Composites Obtained from SHS Powders by Spark Plasma Sintering

by Pavel Nikitin, Ilya Zhukov, Aleksey Matveev, Sergei Sokolov, Mikhail Grigoriev and Alexander Vorozhtsov

Materials 2021, 14(19), 5521; https://doi.org/10.3390/ma14195521 - 24 Sep 2021

Cited by 5 | Viewed by 2093

Abstract

AlMgB₁₄-TiB₂ composite materials were fabricated by self-propagating high-temperature synthesis (SHS) followed by spark plasma sintering of the obtained SHS products. It was found that, during the SHS, the AlMgB₁₄ phase is formed at a donor (Ti + 2B) to [...] Read more.

AlMgB₁₄-TiB₂ composite materials were fabricated by self-propagating high-temperature synthesis (SHS) followed by spark plasma sintering of the obtained SHS products. It was found that, during the SHS, the AlMgB₁₄ phase is formed at a donor (Ti + 2B) to acceptor (Al₁₂Mg₁₇-B) mass ratio of 3:7 and 4:6, respectively. The specimen sintered from the SHS powder with the donor:acceptor mass ratio of 5:5 at a temperature of 1470 °C has a uniform skeletal structure. The average hardness of the obtained specimen is 30.1 GPa. Full article

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22 pages, 9737 KiB

Open AccessArticle

Influence of Mold and Heat Transfer Fluid Materials on the Temperature Distribution of Large Framed Molds in Autoclave Process

by Guowei Zhang, Boming Zhang, Ling Luo, Ting Lin and Xiangchen Xue

Materials 2021, 14(15), 4311; https://doi.org/10.3390/ma14154311 - 1 Aug 2021

Cited by 8 | Viewed by 2777

Abstract

Massive composite components manufactured by autoclave curing in large framed molds are extensively used in the aerospace industry. The high temperature performance of the large framed mold is the key to achieving the desired composite part quality. This paper explores and summarizes the [...] Read more.

Massive composite components manufactured by autoclave curing in large framed molds are extensively used in the aerospace industry. The high temperature performance of the large framed mold is the key to achieving the desired composite part quality. This paper explores and summarizes the important thermal properties of metal and heat transfer fluid materials influencing the heating performance of large framed molds, with the aim of improving the mold temperature distribution. Considering the fluid–thermal–solid interaction inside the autoclave, a reliable computational fluid dynamics (CFD) simulation model was developed and verified by a temperature monitoring experiment to achieve the prediction of the temperature distribution of the large framed mold. Then, numerical simulations were designed on the basis of the CFD model, and the single-variable method was used to study the effects of the material thermal properties on the temperature performance of large framed molds. Our simulation predicts that when copper is used as the mold material, the temperature difference decreases by 30.63% relative to that for steel, and the heating rate increases by 3.45%. Further, when helium is used as the heat transfer medium, the temperature difference decreases by 68.27% relative to that for air, and the heating rate increases by 32.76%. This paper provides a reference for improvement of large framed mold manufacturing and autoclave process in terms of heating rate and temperature uniformity. Full article

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14 pages, 3127 KiB

Open AccessArticle

Design Service Life of RC Structures with Self-Healing Behaviour to Increase Infrastructure Carbon Savings

by Ana Bras, John Milan van der Bergh, Hazha Mohammed and Ismini Nakouti

Materials 2021, 14(12), 3154; https://doi.org/10.3390/ma14123154 - 8 Jun 2021

Cited by 7 | Viewed by 2684

Abstract

Corrosion of reinforced concrete (RC) structures costs the UK GBP 23b annually and is one of the main durability problems contributing to the development of rust, spalling, cracking, delamination, and structural deterioration. This paper intends to demonstrate the benefit of using tailored self-healing [...] Read more.

Corrosion of reinforced concrete (RC) structures costs the UK GBP 23b annually and is one of the main durability problems contributing to the development of rust, spalling, cracking, delamination, and structural deterioration. This paper intends to demonstrate the benefit of using tailored self-healing bacteria-based concrete for RC corrosion minimisation and service life increase. The purpose was to evaluate the enhancement in the lifespan of the structure exposed to a harsh marine microenvironment by utilising a probabilistic performance-based method. Comparison is made with the performance of a commercially available solution and in terms of embodied carbon impact. Three different concretes, using CEM I 52.5N, CEM II/A-D, and CEM III/A, were tested with and without an iron-respiring bioproduct (BIO) and an added admixture corrosion inhibitor (AACI). Results show that bioproduct significantly contributes to service life increase of RC structures with CEMIII/A. The repair solution with self-healing behaviour not only increases RC service life, but also enables us to decrease the required cover thickness from 60 mm to 50 mm in an XS2 chloride environment. In both XS2 and XS3 environments, a comparison of CEMIII/A+BIO and CEMII/A-D+AACI concrete shows the benefit of using bioproduct in corrosion inhibition context, besides contributing to an embodied carbon reduction of more than 20%. Full article

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17 pages, 9378 KiB

Open AccessArticle

Optimization of the Filler Concentration on Fused Filament Fabrication 3D Printed Polypropylene with Titanium Dioxide Nanocomposites

by Nectarios Vidakis, Markos Petousis, Emmanouil Velidakis, Lazaros Tzounis, Nikolaos Mountakis, John Kechagias and Sotirios Grammatikos

Materials 2021, 14(11), 3076; https://doi.org/10.3390/ma14113076 - 4 Jun 2021

Cited by 44 | Viewed by 3704

Abstract

Polypropylene (PP) is an engineered thermoplastic polymer widely used in various applications. This work aims to enhance the properties of PP with the introduction of titanium dioxide (TiO₂) nanoparticles (NPs) as nanofillers. Novel nanocomposite filaments were produced at 0.5, 1, 2, [...] Read more.

Polypropylene (PP) is an engineered thermoplastic polymer widely used in various applications. This work aims to enhance the properties of PP with the introduction of titanium dioxide (TiO₂) nanoparticles (NPs) as nanofillers. Novel nanocomposite filaments were produced at 0.5, 1, 2, and 4 wt.% filler concentrations, following a melt mixing extrusion process. These filaments were then fed to a commercially available fused filament fabrication (FFF) 3D printer for the preparation of specimens, to be assessed for their mechanical, viscoelastic, physicochemical, and fractographic properties, according to international standards. Tensile, flexural, impact, and microhardness tests, as well as dynamic mechanical analysis (DMA), Raman, scanning electron microscopy (SEM), melt flow volume index (MVR), and atomic force microscopy (AFM), were conducted, to fully characterize the filler concentration effect on the 3D printed nanocomposite material properties. The results revealed an improvement in the nanocomposites properties, with the increase of the filler amount, while the microstructural effect and processability of the material was not significantly affected, which is important for the possible industrialization of the reported protocol. This work showed that PP/TiO₂ can be a novel nanocomposite system in AM applications that the polymer industry can benefit from. Full article

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22 pages, 76639 KiB

Open AccessArticle

Fuzzy Logic-Based and Nondestructive Concrete Strength Evaluation Using Modified Carbon Nanotubes as a Hybrid PZT–CNT Sensor

by Najeebullah Tareen, Junkyeong Kim, Won-Kyu Kim and Seunghee Park

Materials 2021, 14(11), 2953; https://doi.org/10.3390/ma14112953 - 30 May 2021

Cited by 7 | Viewed by 2855

Abstract

Concrete strength and factors affecting its development during early concrete curing are important research topics. Avoiding uncertain incidents during construction and in service life of structures requires an appropriate monitoring system. Therefore, numerous techniques are used to monitor the health of a structure. [...] Read more.

Concrete strength and factors affecting its development during early concrete curing are important research topics. Avoiding uncertain incidents during construction and in service life of structures requires an appropriate monitoring system. Therefore, numerous techniques are used to monitor the health of a structure. This paper presents a nondestructive testing technique for monitoring the strength development of concrete at early curing ages. Dispersed carbon nanotubes (CNTs) were used with cementitious materials and piezoelectric (PZT) material, a PZT ceramic, owing to their properties of intra electromechanical effects and sensitivity to measure the electromechanical impedance (EMI) signatures and relevant properties related to concrete strength, such as the elastic modulus, displacement, acceleration, strength, and loading effects. Concrete compressive strength, hydration temperature, mixture ratio, and variation in data obtained from the impedance signatures using fuzzy logic were utilized in the comparative result prediction method for concrete strength. These results were calculated using a fuzzy logic-based model considering the maturity method, universal testing machine (UTM) data, and analyzed EMI data. In the study, for data acquisition, a hybrid PZT–CNT sensor and a temperature sensor (Smart Rock) were embedded in the concrete to obtain the hydration temperature history to utilize the concrete maturity method and provide data on the EMI signatures. The dynamic changes in the medium caused during the phase in the concrete strengthening process were analyzed to predict the strength development process of concrete at early curing ages. Because different parameters are considered while calculating the concrete strength, which is related to its mechanical properties, the proposed novel method considers that changes in the boundary condition occurring in the concrete paste modify the resonant frequency response of the structure. Thus, relating and analyzing this feature can help predict the concrete strength. A comprehensive comparison of the results calculated using the proposed module, maturity method, and cylindrical specimens tested using the UTM proved that it is a cost-effective and fast technique to estimate concrete strength to ensure a safe construction of reinforced cement concrete infrastructures. Full article

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12 pages, 3720 KiB

Open AccessArticle

In Situ Formation of ZrB₂ and Its Influence on Wear and Mechanical Properties of ADC12 Alloy Mixed Matrix Composites

by Lalta Prasad, Niteesh Kumar, Anshul Yadav, Anil Kumar, Virendra Kumar and Jerzy Winczek

Materials 2021, 14(9), 2141; https://doi.org/10.3390/ma14092141 - 23 Apr 2021

Cited by 13 | Viewed by 2708

Abstract

In this work, aluminium alloy ADC12 reinforced with various amounts of ZrB₂ (0 wt.%, 3 wt.%, 6 wt.%, 9 wt.%) were synthesized by an in-situ reaction of molten aluminium with inorganic salts K₂ZrF₆ & KBF_4. XRD, EDAX, and [...] Read more.

In this work, aluminium alloy ADC12 reinforced with various amounts of ZrB₂ (0 wt.%, 3 wt.%, 6 wt.%, 9 wt.%) were synthesized by an in-situ reaction of molten aluminium with inorganic salts K₂ZrF₆ & KBF_4. XRD, EDAX, and SEM techniques are used for the characterization of the fabricated composite. XRD analysis revealed the successful in situ formation of ZrB₂ in the composite. From the SEM images, it was concluded that the distribution of reinforcement was homogeneous in the composites. A study of mechanical and tribological properties under the dry sliding condition of ZrB₂-reinforced ADC12 alloy has also been carried out. It is seen that there is an increase in tensile strength by 18.8%, hardness by 64.2%, and an increase in wear resistance of the material after reinforcement. The ductility of the material decreased considerably with an increase in the amount of reinforcement. The composite’s impact strength decreased by 27.7% because of the addition of hard ZrB₂ particulates. Full article

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16 pages, 93685 KiB

Open AccessArticle

Sustainable Additive Manufacturing: Mechanical Response of Polyethylene Terephthalate Glycol over Multiple Recycling Processes

by Nectarios Vidakis, Markos Petousis, Lazaros Tzounis, Sotirios A. Grammatikos, Emmanouil Porfyrakis, Athena Maniadi and Nikolaos Mountakis

Materials 2021, 14(5), 1162; https://doi.org/10.3390/ma14051162 - 2 Mar 2021

Cited by 68 | Viewed by 5686

Abstract

The continuous demand for thermoplastic polymers in a great variety of applications, combined with an urgent need to minimize the quantity of waste for a balanced energy-from-waste strategy, has led to increasing scientific interest in developing new recycling processes for plastic products. Glycol-modified [...] Read more.

The continuous demand for thermoplastic polymers in a great variety of applications, combined with an urgent need to minimize the quantity of waste for a balanced energy-from-waste strategy, has led to increasing scientific interest in developing new recycling processes for plastic products. Glycol-modified polyethylene terephthalate (PETG) is known to have some enhanced properties as compared to polyethylene terephthalate (PET) homopolymer; this has recently attracted the interest from the fused filament fabrication (FFF) three-dimensional (3D) printing community. PET has shown a reduced ability for repeated recycling through traditional processes. Herein, we demonstrate the potential for using recycled PETG in consecutive 3D printing manufacturing processes. Distributed recycling additive manufacturing (DRAM)-oriented equipment was chosen in order to test the mechanical and thermal response of PETG material in continuous recycling processes. Tensile, flexure, impact strength, and Vickers micro-hardness tests were carried out for six (6) cycles of recycling. Finally, Raman spectroscopy as well as thermal and morphological analyses via scanning electron microscopy (SEM) fractography were carried out. In general, the results revealed a minor knockdown effect on the mechanical properties as well as the thermal properties of PETG following the process proposed herein, even after six rounds of recycling. Full article

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2020

Jump to: 2023, 2022, 2021

15 pages, 9805 KiB

Open AccessArticle

Effects of CeO₂ Content on Friction and Wear Properties of SiCp/Al-Si Composite Prepared by Powder Metallurgy

by Bin Yang, Aiqin Wang, Kunding Liu, Chenlu Liu, Jingpei Xie, Guangxin Wang and Shizhong Wei

Materials 2020, 13(20), 4547; https://doi.org/10.3390/ma13204547 - 13 Oct 2020

Cited by 4 | Viewed by 1699

Abstract

SiCp/Al-Si composites with different CeO₂ contents were prepared by a powder metallurgy method. The effect of CeO₂ content on mechanical properties, friction and wear properties of the composites was studied. The results show that with the increase in CeO₂ content [...] Read more.

SiCp/Al-Si composites with different CeO₂ contents were prepared by a powder metallurgy method. The effect of CeO₂ content on mechanical properties, friction and wear properties of the composites was studied. The results show that with the increase in CeO₂ content from 0 to 1.8 wt%, the density, hardness, friction coefficient of the composites first increases and then decreases, the coefficient of thermal expansion (CTE) and wear rate of the composites first decreases and then increases. When the content of CeO₂ was 0.6 wt%, the density and hardness of the composite reached the maximum value of 98.54% and 113.7 HBW, respectively, the CTE of the composite reached the minimum value of 11.1 × 10⁻⁶ K⁻¹, the friction coefficient and wear rate of the composite reached the maximum value of 0.32 and the minimum value of 1.02 mg/m, respectively. CeO₂ has little effect on the wear mechanism of composites, and the wear mechanism of composites with different CeO₂ content is mainly abrasive wear under the load of 550 N. Compared with the content of CeO₂, load has a great influence on the wear properties of the composites. The wear mechanism of the composites is mainly oxidation wear and abrasive wear under low load. With the increase in load, the wear degree of abrasive particles is aggravated, and adhesive wear occurs under higher load. Full article

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17 pages, 6589 KiB

Open AccessArticle

Impact Resistance Study of Three-Dimensional Orthogonal Carbon Fibers/BMI Resin Woven Composites

by Yanqi Hu, Zekan He and Haijun Xuan

Materials 2020, 13(19), 4376; https://doi.org/10.3390/ma13194376 - 1 Oct 2020

Cited by 5 | Viewed by 2432

Abstract

Three-dimensional woven composites have been reported to have superior fracture toughness, fatigue life and damage tolerance compared with laminated composites due to through-thickness reinforcement. These properties make them lighter replacements for traditional high-strength metals and laminated composites. This paper will present impact resistance [...] Read more.

Three-dimensional woven composites have been reported to have superior fracture toughness, fatigue life and damage tolerance compared with laminated composites due to through-thickness reinforcement. These properties make them lighter replacements for traditional high-strength metals and laminated composites. This paper will present impact resistance research on three-dimensional orthogonal woven composites consisting of carbon fibers/bismaleimide resin (BMI). A series of impact tests were conducted using the gas gun technique with the impacted target of 150 mm × 150 mm × 8 mm (length × width × thickness) and the cylindrical titanium projectile. The projectile velocity ranged from 180 m/s to 280 m/s, generating different results from rebound to perforation. This paper also presents a multiscale modeling strategy to investigate the damage and failure behavior of three-dimensional woven composites. The microscale and mesoscale are identified to consider the fiber/matrix scale and the tow architecture scale respectively. The macroscale model was effective with homogenized feature. Then a combined meso-macroscale model was developed with the interface definitions for component analysis in the explicit dynamic software LS-DYNA. The presented results showed reliable interface connection and can be used to study localized composites damage at a relatively high efficiency. Full article

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10 pages, 5371 KiB

Open AccessArticle

Effects of CeO₂ on the Si Precipitation Mechanism of SiCp/Al-Si Composite Prepared by Powder Metallurgy

by Bin Yang, Aiqin Wang, Kunding Liu, Chenlu Liu, Jingpei Xie, Guangxin Wang and Shizhong Wei

Materials 2020, 13(19), 4365; https://doi.org/10.3390/ma13194365 - 30 Sep 2020

Cited by 1 | Viewed by 1638

Abstract

SiCp/Al-Si composites with different CeO₂ contents were prepared by a powder metallurgy method. The effect of CeO₂ content on the microstructure of the composites was studied. The mechanism of CeO₂ on the precipitation of Si during sintering was analyzed by [...] Read more.

SiCp/Al-Si composites with different CeO₂ contents were prepared by a powder metallurgy method. The effect of CeO₂ content on the microstructure of the composites was studied. The mechanism of CeO₂ on the precipitation of Si during sintering was analyzed by theoretical calculations. The results show that the appropriate amount of CeO₂ can significantly refine the size of precipitated Si particles in the composite and increase the number of Si particles. With the increase of CeO₂ content from 0 to 0.6 wt%, the number of Si particles precipitated in the composites increases gradually, and the average particle size of Si particles decreases gradually. When the CeO₂ content is 0.6 wt%, the number of Si particles precipitated in the composites reaches the maximum, and the average particle size reaches the minimum. However, with the increase of CeO₂ content from 0.6 wt% to 1.8 wt%, the number of Si particles precipitated in the composites began to decrease, and the average size of Si particles gradually increased. CeO₂ can be used as heterogeneous nucleation substrate of precipitated Si, and the nucleation rate of precipitated Si on a CeO₂ substrate is higher than that on an aluminum substrate. The proper addition of CeO₂ can improve the nucleation efficiency of precipitated Si, thus increasing the amount and refining the size of precipitated Si. Full article

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12 pages, 6649 KiB

Open AccessArticle

An Investigation of Microstructural Evolution, Tensile Properties and Work-Hardening Behavior of Nanosized TiB₂/Al-Cu-Mn Composites

by Cun Juan Xia, Lei Wang, Qing Zhang, Hao Fei Zhu, Jun Liu, Feng Guo Zhang, Zhe Chen and Hao Wei Wang

Materials 2020, 13(19), 4250; https://doi.org/10.3390/ma13194250 - 24 Sep 2020

Cited by 5 | Viewed by 2280

Abstract

The microstructure evolution, tensile properties and work-hardening behavior of AA2219 alloy reinforced by in situ nanosized TiB₂ particles were studied in this paper. The observation indicated an impeded recrystallization of the matrix alloy by nanosized TiB₂ particles, and the hybrids of [...] Read more.

The microstructure evolution, tensile properties and work-hardening behavior of AA2219 alloy reinforced by in situ nanosized TiB₂ particles were studied in this paper. The observation indicated an impeded recrystallization of the matrix alloy by nanosized TiB₂ particles, and the hybrids of nanosized TiB₂ particles and Al₂Cu phases located at the grain boundary hindered the grain growth. Meanwhile, a large amount fiber textures of <111>//RD (Rolling direction), <110>//RD, <100>//RD <111>//ND (Normal direction), <110>//ND and <100>//ND were detected in nanosized TiB₂/AA2219 composite. Tensile test results exhibited a combination of good strength and ductility of the present composite whose yield strength and tensile strength were 11.4% and 5.8% higher than those of the alloy, while its fracture strain increased slightly. Meanwhile, the correlation between this modified microstructure of nanosized TiB₂ particles and comprehensive mechanical properties was established. This study provides a new insight into the fabrication and strengthening behaviors of Al matrix composites reinforced by in situ nanoparticles. Full article

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15 pages, 6562 KiB

Open AccessArticle

Influence of the Anisotropy on the Microstructure and Mechanical Properties of Ti/Al Laminated Composites

by Tao Huang, Zhuo Song, Fuxiao Chen, Junqing Guo, Yanbo Pei, Binghui Xing, Nan Xiang and Kexing Song

Materials 2020, 13(16), 3556; https://doi.org/10.3390/ma13163556 - 12 Aug 2020

Cited by 16 | Viewed by 2533

Abstract

Anisotropy is the difference in the microstructure or mechanical properties of materials in different directions. Anisotropic behavior occurs in rolled sheets, and this anisotropy is very obvious in laminated composites. In this work, the influence of anisotropy on the microstructure and mechanical properties [...] Read more.

Anisotropy is the difference in the microstructure or mechanical properties of materials in different directions. Anisotropic behavior occurs in rolled sheets, and this anisotropy is very obvious in laminated composites. In this work, the influence of anisotropy on the microstructure and mechanical properties of Ti/Al laminated composites fabricated by rolling was investigated. The results show that the microstructure and mechanical properties of the Ti/Al laminated composites were obviously anisotropic. The grains in the Al layer of the composites were elongated along the rolling direction and were compressed perpendicular to the rolling direction. The grains in the Ti layer of the composites had no obvious preferential orientation and comprised mainly twins. With the rolling direction as 0°, the mechanical properties of the Ti/Al laminated composites varied greatly as the angle of the composites increased. The tensile strength, elongation and bond strength of the Ti/Al laminated composites decreased with increasing angle of the composites. In addition, the microhardness of the Ti/Al laminated composites increased with increasing angle of the composites. Full article

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18 pages, 13572 KiB

Open AccessArticle

Influence of Aluminum Surface Treatment on Tensile and Fatigue Behavior of Thermoplastic-Based Hybrid Laminates

by Selim Mrzljak, Maik Trautmann, Guntram Wagner and Frank Walther

Materials 2020, 13(14), 3080; https://doi.org/10.3390/ma13143080 - 10 Jul 2020

Cited by 11 | Viewed by 3272

Abstract

Hybrid laminates consist of layers of different materials, which determine the mechanical properties of the laminate itself. Furthermore, the structure and interfacial properties between the layers play a key role regarding the performance under load and therefore need to be investigated in respect [...] Read more.

Hybrid laminates consist of layers of different materials, which determine the mechanical properties of the laminate itself. Furthermore, the structure and interfacial properties between the layers play a key role regarding the performance under load and therefore need to be investigated in respect to industrial applicability. In this regard, a hybrid laminate comprised of AA6082 aluminum alloy sheets and glass and carbon fiber-reinforced thermoplastic (polyamide 6) is investigated in this study with a focus on the influence of aluminum surface treatment application on tensile and fatigue behavior. Four different aluminum surface treatments are discussed (adhesion promoter, mechanical blasting, phosphating, and anodizing), which were characterized by Laser Scanning Microscopy. After the thermal consolidation of the hybrid laminate under defined pressure, double notch shear tests and tensile tests were performed and correlated to determine the resulting interfacial strength between the aluminum sheet surface and the fiber-reinforced plastic, and its impact on tensile performance. To investigate the performance of the laminate under fatigue load in LCF and HCF regimes, a short-time procedure was applied consisting of resource-efficient instrumented multiple and constant amplitude tests. Digital image correlation, thermography, and hysteresis measurement methods were utilized to gain information about the aluminum surface treatment influence on fatigue damage initiation and development. The results show that fatigue-induced damage initiation, development, and mechanisms differ significantly depending on the applied aluminum surface treatment. The used measurement technologies proved to be suitable for this application and enabled correlations in between, showing that the hybrid laminates damage state, in particular regarding the interfacial bonding of the layers, can be monitored not just through visual recordings of local strain and temperature development, but also through stress-displacement hysteresis analysis. Full article

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14 pages, 9090 KiB

Open AccessArticle

High Temperature Mechanical Properties of a Vented Ti-6Al-4V Honeycomb Sandwich Panel

by Lei Shang, Ye Wu, Yuchao Fang and Yao Li

Materials 2020, 13(13), 3008; https://doi.org/10.3390/ma13133008 - 6 Jul 2020

Cited by 14 | Viewed by 3110

Abstract

For aerospace applications, honeycomb sandwich panels may have small perforations on the cell walls of the honeycomb core to equilibrate the internal core pressure with external gas pressure, which prevent face-sheet/core debonding due to pressure build-up at high temperature. We propose a new [...] Read more.

For aerospace applications, honeycomb sandwich panels may have small perforations on the cell walls of the honeycomb core to equilibrate the internal core pressure with external gas pressure, which prevent face-sheet/core debonding due to pressure build-up at high temperature. We propose a new form of perforation on the cell walls of honeycomb sandwich panels to reduce the influence of the perforations on the cell walls on the mechanical properties. In this paper, the high temperature mechanical properties of a new vented Ti-6Al-4V honeycomb sandwich panel were investigated. A vented Ti-6AL-4V honeycomb sandwich panel with 35Ti-35Zr-15Cu-15Ni as the filler alloy was manufactured by high-temperature brazing. The element distribution of the brazed joints was examined by means of SEM (scanning electron microscopy) and EDS (energy-dispersive spectroscopy) analyses. Compared to the interaction between the face-sheets and the brazing filler, the diffusion and reaction between the honeycomb core and the brazing filler were stronger. The flatwise compression and flexural mechanical properties of the vented honeycomb sandwich panels were investigated at 20, 160, 300, and 440 °C, respectively. The flatwise compression strength, elastic modulus, and the flexural strength of the vented honeycomb sandwich panels decreased with the increase of temperature. Moreover, the flexural strength of the L-direction sandwich panels was larger than that of the W-direction sandwich panels at the same temperature. More importantly, the vented honeycomb sandwich panels exhibited good compression performance similar to the unvented honeycomb sandwich panels, and the open holes on the cell walls have no negative effect on the compression performance of the honeycomb sandwich panels in these conditions. The damage morphology observed by SEM revealed that the face-sheets and the brazing zone show ductile and brittle fracture behaviors, respectively. Full article

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17 pages, 5328 KiB

Open AccessArticle

3D Printed Thermoelectric Polyurethane/Multiwalled Carbon Nanotube Nanocomposites: A Novel Approach towards the Fabrication of Flexible and Stretchable Organic Thermoelectrics

by Lazaros Tzounis, Markos Petousis, Sotirios Grammatikos and Nectarios Vidakis

Materials 2020, 13(12), 2879; https://doi.org/10.3390/ma13122879 - 26 Jun 2020

Cited by 60 | Viewed by 5617

Abstract

Three-dimensional (3D) printing of thermoelectric polymer nanocomposites is reported for the first time employing flexible, stretchable and electrically conductive 3D printable thermoplastic polyurethane (TPU)/multiwalled carbon nanotube (MWCNT) filaments. TPU/MWCNT conductive polymer composites (CPC) have been initially developed employing melt-mixing and extrusion processes. TPU [...] Read more.

Three-dimensional (3D) printing of thermoelectric polymer nanocomposites is reported for the first time employing flexible, stretchable and electrically conductive 3D printable thermoplastic polyurethane (TPU)/multiwalled carbon nanotube (MWCNT) filaments. TPU/MWCNT conductive polymer composites (CPC) have been initially developed employing melt-mixing and extrusion processes. TPU pellets and two different types of MWCNTs, namely the NC-7000 MWCNTs (NC-MWCNT) and Long MWCNTs (L-MWCNT) were used to manufacture TPU/MWCNT nanocomposite filaments with 1.0, 2.5 and 5.0 wt.%. 3D printed thermoelectric TPU/MWCNT nanocomposites were fabricated through a fused deposition modelling (FDM) process. Raman and scanning electron microscopy (SEM) revealed the graphitic nature and morphological characteristics of CNTs. SEM and transmission electron microscopy (TEM) exhibited an excellent CNT nanodispersion in the TPU matrix. Tensile tests showed no significant deterioration of the moduli and strengths for the 3D printed samples compared to the nanocomposites prepared by compression moulding, indicating an excellent interlayer adhesion and mechanical performance of the 3D printed nanocomposites. Electrical and thermoelectric investigations showed that L-MWCNT exhibits 19.8 ± 0.2 µV/K Seebeck coefficient (S) and 8.4 × 10³ S/m electrical conductivity (σ), while TPU/L-MWCNT CPCs at 5.0 wt.% exhibited the highest thermoelectric performance (σ = 133.1 S/m, S = 19.8 ± 0.2 µV/K and PF = 0.04 μW/mK²) among TPU/CNT CPCs in the literature. All 3D printed samples exhibited an anisotropic electrical conductivity and the same Seebeck coefficient in the through- and cross-layer printing directions. TPU/MWCNT could act as excellent organic thermoelectric material towards 3D printed thermoelectric generators (TEGs) for potential large-scale energy harvesting applications. Full article

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12 pages, 4250 KiB

Open AccessArticle

Three-Dimensional (3D) Conductive Network of CNT-Modified Short Jute Fiber-Reinforced Natural Rubber: Hierarchical CNT-Enabled Thermoelectric and Electrically Conductive Composite Interfaces

by Lazaros Tzounis, Markos Petousis, Marco Liebscher, Sotirios Grammatikos and Nectarios Vidakis

Materials 2020, 13(11), 2668; https://doi.org/10.3390/ma13112668 - 11 Jun 2020

Cited by 14 | Viewed by 4154

Abstract

Jute fibers (JFs) coated with multiwall carbon nanotubes (MWCNTs) have been introduced in a natural rubber (NR) matrix creating a three-dimensional (3D) electrically conductive percolated network. The JF-CNT endowed electrical conductivity and thermoelectric properties to the final composites. CNT networks fully covered the [...] Read more.

Jute fibers (JFs) coated with multiwall carbon nanotubes (MWCNTs) have been introduced in a natural rubber (NR) matrix creating a three-dimensional (3D) electrically conductive percolated network. The JF-CNT endowed electrical conductivity and thermoelectric properties to the final composites. CNT networks fully covered the fiber surfaces as shown by the corresponding scanning electron microscopy (SEM) analysis. NR/JF-CNT composites, at 10, 20 and 30 phr (parts per hundred gram of rubber) have been manufactured using a two-roll mixing process. The highest value of electrical conductivity (σ) was 81 S/m for the 30 phr composite. Thermoelectric measurements revealed slight differences in the Seebeck coefficient (S), while the highest power factor (PF) was 1.80 × 10⁻² μW/m K⁻² for the 30 phr loading. The micromechanical properties and electrical response of the composite’s conductive interface have been studied in peak force tapping quantitative nanomechanical (PFT QNM) and conductive atomic force microscopy (c-AFM) mode. The JF-CNT create an electrically percolated network at all fiber loadings endowing electrical and thermoelectric properties to the NR matrix, considered thus as promising thermoelectric stretchable materials. Full article

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13 pages, 4873 KiB

Open AccessArticle

Copper Filled Poly(Acrylonitrile-co-Butadiene-co-Styrene) Composites for Laser-Assisted Selective Metallization

by Piotr Rytlewski, Bartłomiej Jagodziński, Tomasz Karasiewicz, Piotr Augustyn, Daniel Kaczor, Rafał Malinowski, Krzysztof Szabliński, Marcin Mazurkiewicz and Krzysztof Moraczewski

Materials 2020, 13(10), 2224; https://doi.org/10.3390/ma13102224 - 12 May 2020

Cited by 6 | Viewed by 2591

Abstract

Selective metallization of polymeric materials using the technique known as laser direct structuring (LDS) is intensively developed. In this technique, metallized products can be manufactured by injection molding or by 3D printing process if rapid prototyping is need. Special additives present in the [...] Read more.

Selective metallization of polymeric materials using the technique known as laser direct structuring (LDS) is intensively developed. In this technique, metallized products can be manufactured by injection molding or by 3D printing process if rapid prototyping is need. Special additives present in the polymer matrix enable direct electroless metallization only on the surface which was laser activated. This paper presents the results of using copper microparticles introduced into the poly(acrylonitrile-butadiene-styrene) (ABS) matrix at various amounts (up to about 5 vol %). ABS was selected due to its good processing and mechanical properties and as one of the most common thermoplastics used in 3D printing. The influence of copper on structural, mechanical, and processing properties as well as on the effects of laser surface activation were determined. Two types of infrared lasers were tested for surface activation: Nd:YAG fiber laser (λ = 1064 nm) and CO₂ laser (λ = 10.6 µm). Various irradiation parameters (power, scanning speed, and frequency) were applied to find suitable conditions for laser surface activation and electroless metallization. It was found that the composites tested can be effectively metallized using the Nd:YAG laser, but only in a narrow range of radiation parameters. Activation with CO₂ laser failed, regardless of applied irradiation conditions. It resulted from the fact that ablation rate and thickness of modified surface layer for CO₂ were lower than for Nd:YAG laser using the same irradiation parameters (power, speed, and frequency of laser beams), thus the laser wavelength was crucial for successful surface activation. Full article

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17 pages, 5174 KiB

Open AccessArticle

Experimental Study on Mechanical Properties of the Sandwich Composite Structure Reinforced by Basalt Fiber and Nomex Honeycomb

by Zongwen Li and Jianxun Ma

Materials 2020, 13(8), 1870; https://doi.org/10.3390/ma13081870 - 16 Apr 2020

Cited by 32 | Viewed by 6379

Abstract

The new sandwich composite structure formed by basalt fiber resin-based sheets and Nomex honeycomb has the advantages of being lightweight and environmentally friendly, as well as having excellent electromagnetic performance. It has very important application prospects in traditional and emerging fields. In this [...] Read more.

The new sandwich composite structure formed by basalt fiber resin-based sheets and Nomex honeycomb has the advantages of being lightweight and environmentally friendly, as well as having excellent electromagnetic performance. It has very important application prospects in traditional and emerging fields. In this paper, the mechanical properties of this new sandwich composite structure are studied. The results show that, under the condition of flatwise compression, increasing the height of the honeycomb is conducive to improving the compressive capacity of the structure. However, the height should be controlled within a certain range in case of instability and yield of the honeycomb; under the bending conditions, the bending failure mode of the composite structure has gone through five stages. Owing to the honeycomb manufacturing process, the orientation of the honeycomb also has a great influence on the bending strength of the structure. After further analysis, it is found that basalt fiber sheets contribute the most to the bending stiffness of the structure, and the main role of honeycomb is to provide out-of-plane support. In both cases, the failure of specimens is ductile, and the combined structure still has a small amount of bearing capacity and maintains structural integrity. Research on this new type of composite structural material is very beneficial for promoting the application and development of green and lightweight special functional materials. Full article

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