Metals

13 pages, 2714 KiB

Open AccessArticle

Effect of Yttrium and Yttria Addition in Self-Passivating WCr SMART Material for First-Wall Application in a Fusion Power Plant

by Jie Chen, Elena Tejado, Marcin Rasiński, Andrey Litnovsky, Duc Nguyen-Manh, Eric Prestat, Tamsin Whitfield, Jose Ygnacio Pastor, Martin Bram, Jan Willem Coenen, Christian Linsmeier and Jesus Gonzalez-Julian

Metals 2024, 14(9), 1092; https://doi.org/10.3390/met14091092 - 23 Sep 2024

Viewed by 777

Abstract

The self-passivating yttrium-containing WCr alloy has been developed and researched as a potential plasma-facing armour material for fusion power plants. This study explores the use of yttria (Y₂O₃) powders instead of yttrium elemental powders in the mechanical alloying process [...] Read more.

The self-passivating yttrium-containing WCr alloy has been developed and researched as a potential plasma-facing armour material for fusion power plants. This study explores the use of yttria (Y₂O₃) powders instead of yttrium elemental powders in the mechanical alloying process to assess their applicability for this material. Fabricated through field-assisted sintering, WCr-Y₂O₃ ingots show Y₂O₃ and Cr-containing oxides (Cr-O and Y-Cr-O) dispersed at grain boundaries (GBs), while WCrY ingots contain Y-O particles at grain boundaries, both resulting from unavoidable oxidation during fabrication. WCr-Y₂O₃ demonstrates higher flexural strength than WCrY across all temperature ranges, ranging from 850 to 1050 MPa, but lower fracture toughness, between 3 and 4 MPa·√m. Enhanced oxidation resistance is observed in WCr-Y₂O₃, with lower mass gain as compared to WCrY during the 20-hour oxidation test. This study confirms the effectiveness of both yttria and yttrium in the reactive element effect (REE) for the passivation of WCr alloy, suggesting the potential of Y₂O₃-doped WCr for first wall applications in a fusion power plant. Full article

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21 pages, 8252 KiB

Open AccessArticle

Experimental Investigation of the Influence of Phase Compounds on the Friability of Fe-Si-Mn-Al Complex Alloy

by Talgat Zhuniskaliyev, Assylbek Nurumgaliyev, Askar Chekimbayev, Bauyrzhan Kelamanov, Yerbol Kuatbay, Yerbol Mukhambetgaliyev, Azamat Mukhambetkaliyev and Assylbek Abdirashit

Metals 2024, 14(9), 1091; https://doi.org/10.3390/met14091091 - 23 Sep 2024

Viewed by 754

Abstract

The research presented in the article is devoted to the study of the influence of phase compounds on the friability of the Fe-Si-Mn-Al complex alloy. The urgency of the problem lies in the development of technology for producing a non-scatterable alloy from manganese-containing [...] Read more.

The research presented in the article is devoted to the study of the influence of phase compounds on the friability of the Fe-Si-Mn-Al complex alloy. The urgency of the problem lies in the development of technology for producing a non-scatterable alloy from manganese-containing ores and high-ash coals. The main goal of this work is to determine the range of alloy compositions and the resulting phases that affect the dispersibility of the alloy, which is critically important for its industrial implementation. Research methods include thermodynamic diagram analysis (TDA) using data on the standard enthalpy of formation of intermetallic compounds, as well as experimental tests in an ore-thermal electric furnace with a capacity of 200 kV*A. The results show that Fe-Si-Mn-Al complex alloys form a variety of silicide and aluminide phases, including intermetallic compounds and ternary systems, which is critical for understanding and controlling their physicochemical properties. When melting a complex alloy, the content of leboite (Fe₃Si₇) in the Fe-Si-Mn-Al system plays a significant role. The development of melting process technology will be aimed at avoiding the FeSi₂-Fe₃Si₇-F₂(FeAl₃Si₂)-Mn₁₁Si₁₉ tetrahedron area. This approach to controlling the composition of a complex alloy is critical to ensuring its consistent friability properties in industrial applications. Thus, this work represents an important step in understanding the physical properties and stability of Fe-Si-Mn-Al complex alloys, which have potential for widespread use in metallurgical and other industrial applications. Full article

(This article belongs to the Section Entropic Alloys and Meta-Metals)

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9 pages, 2886 KiB

Open AccessArticle

Effects of CTAB (Cetyltrimethylammonium Bromide) and Betaine as Corrosion Inhibitors on the Galvanic Corrosion of Cu Coupled with Au on Print Circuit Board in Etching Solution

by HeeKwon Shin and SeKwon Oh

Metals 2024, 14(9), 1090; https://doi.org/10.3390/met14091090 - 23 Sep 2024

Viewed by 692

Abstract

This study investigates the suppression of galvanic corrosion between copper and gold using cetyltrimethylammonium bromide (CTAB) and betaine as inhibitors. When copper is electrically connected to gold in PCB etching solutions, the substantial difference in their electrochemical potentials leads to the accelerated corrosion [...] Read more.

This study investigates the suppression of galvanic corrosion between copper and gold using cetyltrimethylammonium bromide (CTAB) and betaine as inhibitors. When copper is electrically connected to gold in PCB etching solutions, the substantial difference in their electrochemical potentials leads to the accelerated corrosion of copper, posing severe reliability risks. To mitigate this, we systematically investigated the galvanic corrosion inhibition properties of CTAB and betaine. Through comprehensive electrochemical analyses, it was found that the galvanic corrosion current density of copper, initially at 3.26 mA/cm², decreased significantly to 0.251 mA/cm² with 0.9 mM CTAB, indicating an inhibition efficiency of 92.3%. Furthermore, betaine, at a concentration of 0.1 mM, demonstrated an even higher inhibition efficiency, reducing the corrosion current to 0.03 mA/cm², achieving a 99.1% inhibition rate. These findings provide strong evidence that CTAB and betaine are highly effective in suppressing galvanic corrosion in copper–gold systems, thereby enhancing the long-term performance and reliability of PCBs in electronic applications. Full article

(This article belongs to the Special Issue Advances in Corrosion and Protection of Materials (Second Edition))

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11 pages, 6705 KiB

Open AccessArticle

Realization of Friction Stir Welding of Aluminum Alloy AA5754 Using a Ceramic Tool

by Toni Sprigode, Andreas Gester, Guntram Wagner and Ulrich Degenhardt

Metals 2024, 14(9), 1089; https://doi.org/10.3390/met14091089 - 23 Sep 2024

Cited by 1 | Viewed by 728

Abstract

When engaging in the friction stir welding of aluminum/aluminum joints, the conventional use of tools made of hard metal and steel involves a complex and costly production process. These tools experience wear over welding distances and require frequent replacement to ensure the consistency [...] Read more.

When engaging in the friction stir welding of aluminum/aluminum joints, the conventional use of tools made of hard metal and steel involves a complex and costly production process. These tools experience wear over welding distances and require frequent replacement to ensure the consistency of the welded seams. The exploration of silicon nitrite as a tool material emerges as a promising alternative in this scenario. The heightened hardness of non-oxide ceramics anticipates a diminished wear rate compared to traditional welding materials, translating into an extended operational lifespan. Nevertheless, the adoption of ceramics introduces challenges initially perceived as detrimental to friction stir welding. The inherent brittleness of silicon nitrite makes it susceptible to breakage under specific loads, and thermal stresses within the component can lead to failure. To mitigate these vulnerabilities, a ceramic material with high thermal shock resistance and a low proportion of sintering additives was used. Employing these accurately designed tools friction stir welding (FSW) was performed on sheets of AA5754, followed by a comprehensive examination of their microstructural and mechanical properties. It was demonstrated that a joint efficiency of 88% can be achieved, and that an increase in hardness within the stir zone occurred as a consequence of grain refinement. Furthermore, the Portevin–Le Chatelier effect, which is characteristic of this alloy, was influenced by the FSW process. Full article

(This article belongs to the Special Issue Recent Trends in Friction Stir-Related Manufacturing Technologies)

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13 pages, 10605 KiB

Open AccessArticle

Surface Reaction-Diffusion-Coupled Simulation of Ni–Fe–Cr Alloy under FLiNaK Molten Salt

by Maehyun Cho, Michael R. Tonks and Kunok Chang

Metals 2024, 14(9), 1088; https://doi.org/10.3390/met14091088 - 23 Sep 2024

Viewed by 601

Abstract

A molten salt reactor is one of the fourth-generation reactors and is considered to be a feasible replacement for current reactors due to their many advantages. However, there are a number of issues that remain; one of which is the corrosion of the [...] Read more.

A molten salt reactor is one of the fourth-generation reactors and is considered to be a feasible replacement for current reactors due to their many advantages. However, there are a number of issues that remain; one of which is the corrosion of the materials. Corrosion problems in molten salt reactors have been reported since The Molten Salt Reactor Experiment at Oak Ridge National Laboratory in the 1960s. There have been many attempts to mitigate the corrosion problem, but a fundamental solution has not yet been achived. In this study, surface reaction-diffusion-coupled simulations were performed to simulate the corrosion of a Ni–Cr–Fe material, a prototype of Hastelloy N, which is being promoted as a structural material for molten salt reactors in F–Li–Na–K eutectic salts. This surface reaction-diffusion-coupled simulation framework was developed to study which corrosion reactions are dominant in molten salt environment corrosion where a large number of oxidation–reduction reactions exist, the correlation between composition of alloy and corrosion rate, and the effect of Cr depletion on corrosion. Full article

(This article belongs to the Section Computation and Simulation on Metals)

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17 pages, 2561 KiB

Open AccessArticle

Comparative Study of Steel Mill Dust Leaching with Phosphoric Acid and Sodium Hydroxide

by Fernando Sánchez, Ernesto de la Torre, Alicia Guevara, Katherine Moreno and Carlos F. Aragón-Tobar

Metals 2024, 14(9), 1087; https://doi.org/10.3390/met14091087 - 23 Sep 2024

Viewed by 1100

Abstract

Steel mill dust (SMD), produced by electric arc furnaces, is a highly polluting industrial waste due to its high content of metals (Zn, Fe, and Pb) and fine particle size (ca. 5.4 µm). This residue can be valorized to recover Zn using pyro [...] Read more.

Steel mill dust (SMD), produced by electric arc furnaces, is a highly polluting industrial waste due to its high content of metals (Zn, Fe, and Pb) and fine particle size (ca. 5.4 µm). This residue can be valorized to recover Zn using pyro and hydrometallurgical methods, with hydrometallurgy offering greater selectivity and lower energy costs. However, composition of SMD presents a challenge in identifying an optimal leaching agent. This study investigates the preferential extraction of Zn using two leaching agents, namely 150 g L⁻¹ (1.5 M) phosphoric acid (H₃PO₄) and 240 g L⁻¹ (6 M) sodium hydroxide (NaOH), in a two-stage leaching process (80 °C). Metallic Zn from the alkaline pregnant solution was recovered by electrodeposition (750 A/m², graphite anode, stainless-steel cathode) and smelting (450 °C). The samples of SMD contained 26.3% Zn, 20.1% Fe, and 0.9% Pb, in compounds such as magnetite (Fe₃O₄), zincite (ZnO), and franklinite (ZnFe₂O₄). Each leaching agent successfully attained a 99% Zn recovery, demonstrating the proposed procedure’s high efficacy. However, H₃PO₄ leached also Fe and corroded the cathode during electrodeposition, thereby restricting the final recovery of metallic Zn. NaOH demonstrated greater selectivity for Zn over Fe and Pb, producing high-purity Zn deposits on the cathode by electrodeposition and 99% metallic zinc by smelting. Full article

(This article belongs to the Special Issue Recovery and Utilization of Metallurgical Solid Wastes)

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27 pages, 2408 KiB

Open AccessArticle

Study of the Thermomechanical Behavior of Single-Crystal and Polycrystal Copper

by Sudip Kunda, Noah J. Schmelzer, Akhilesh Pedgaonkar, Jack E. Rees, Samuel D. Dunham, Charles K. C. Lieou, Justin C. M. Langbaum and Curt A. Bronkhorst

Metals 2024, 14(9), 1086; https://doi.org/10.3390/met14091086 - 22 Sep 2024

Viewed by 904

Abstract

This research paper presents an experimental, theoretical, and numerical study of the thermomechanical behavior of single-crystal and polycrystal copper under uniaxial stress compression loading at varying rates of deformation. The thermomechanical theory is based on a thermodynamically consistent framework for single-crystal face-centered cubic [...] Read more.

This research paper presents an experimental, theoretical, and numerical study of the thermomechanical behavior of single-crystal and polycrystal copper under uniaxial stress compression loading at varying rates of deformation. The thermomechanical theory is based on a thermodynamically consistent framework for single-crystal face-centered cubic metals, and assumes that all plastic power is partitioned between stored energy due to dislocation structure evolution (configurational) and thermal (kinetic vibrational) energy. An expression for the Taylor–Quinney factor is proposed, which is a simple function of effective temperature and is allowed by second-law restrictions. This single-crystal model is used for the study of single- and polycrystal copper. New polycrystal thermomechanical experimental results are presented at varying strain rates. The temperature evolution on the surface of the polycrystal samples is measured using mounted thermocouples. Thermomechanical numerical single- and polycrystal simulations were performed for all experimental conditions ranging between

10^{- 3}

and 5 ×

10^{3}

s^{- 1}

. A Taylor homogenization model is used to represent polycrystal behavior. The numerical simulations of all conditions compare reasonable well with experimental results for both stress and temperature evolution. Given our lack of understanding of the mechanisms responsible for the coupling of dislocation glide and atomic vibration, this implies that the proposed theory is a reasonably accurate approximation of the single-crystal thermomechanics. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Metal Crystal/Polycrystal Plastic Strain Hardening)

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13 pages, 23660 KiB

Open AccessArticle

In Situ Microstructural Evolution and Precipitate Analysis of High-Nickel Shipbuilding Steel Using High-Temperature Confocal Laser-Scanning Microscopy

by Guojin Sun, Shengzhi Zhu, Zhenggui Li and Qi Wang

Metals 2024, 14(9), 1085; https://doi.org/10.3390/met14091085 - 22 Sep 2024

Viewed by 797

Abstract

This study investigates the microstructural evolution and mechanical properties of high-nickel shipbuilding steel during thermal processing using high-temperature confocal laser-scanning microscopy (HTCLSM). An in situ observation of the heating and holding processes reveals critical insights into phase transformations, grain-growth behavior, and the formation [...] Read more.

This study investigates the microstructural evolution and mechanical properties of high-nickel shipbuilding steel during thermal processing using high-temperature confocal laser-scanning microscopy (HTCLSM). An in situ observation of the heating and holding processes reveals critical insights into phase transformations, grain-growth behavior, and the formation of precipitates. The experimental results demonstrate that austenitization begins at approximately 700 °C, with significant grain-boundary nucleation. At 900 °C, the formation of black precipitates was observed, and their persistence up to temperatures exceeding 1000 °C was confirmed. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analyses identified these precipitates as chromium carbides (Cr₇C₃), which significantly contribute to the material’s strength. A comprehensive analysis using transmission electron microscopy (TEM) confirmed the presence and distribution of Cr₇C₃ within the grains and along grain boundaries. These findings provide a deeper understanding of the microstructural dynamics in high-nickel steels, guiding the optimization of heat-treatment processes to enhance mechanical properties for maritime applications. Full article

(This article belongs to the Special Issue Phase Transformation and Softening Mechanisms of Metals and Alloys during Thermomechanical Processing)

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26 pages, 16057 KiB

Open AccessArticle

Effect of Residual Stresses on the Fatigue Stress Range of a Pre-Deformed Stainless Steel AISI 316L Exposed to Combined Loading

by Darko Jagarinec and Nenad Gubeljak

Metals 2024, 14(9), 1084; https://doi.org/10.3390/met14091084 - 21 Sep 2024

Cited by 1 | Viewed by 711

Abstract

AISI 316L austenitic stainless steel is utilized in various processing industries, due to its abrasion resistance, corrosion resistance, and excellent properties over a wide temperature range. The physical and mechanical properties of a material change during the manufacturing process and plastic deformation, e.g., [...] Read more.

AISI 316L austenitic stainless steel is utilized in various processing industries, due to its abrasion resistance, corrosion resistance, and excellent properties over a wide temperature range. The physical and mechanical properties of a material change during the manufacturing process and plastic deformation, e.g., bending. During the combined tensile and bending loading of a structural component, the stress state changes due to the residual stresses and the loading range. To characterize the component’s stress state, the billet was bent to induce residual stress, but a phase transformation to martensite also occurred. The bent billet was subjected to combined tensile–bending and fatigue loading. The experimentally measured the load vs. displacement of the bent billet was compared with the numerical simulations. The results showed that during fatigue loading of the bent billet, both the initial stress state at the critical point and the stress state during the dynamic loading itself must be considered. Analysis was demonstrated only for one single critical point on the surface of the bent billet. The residual stresses due to the phase transformation of austenite to martensite affected the range and ratio of stress. The model for the stress–strain behaviour of the material was established by comparing the experimentally and numerically obtained load vs. displacement curves. Based on the description of the stress–strain behaviour of the pre-deformed material, guidelines have been provided for reducing residual tensile stresses in pre-deformed structural components. Full article

(This article belongs to the Special Issue Fatigue, Fracture and Damage of Steels—2nd Edition)

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14 pages, 2171 KiB

Open AccessArticle

Enhanced Mechanical Properties of Ceramic Rod-Reinforced TWIP Steel Composites: Fabrication, Microstructural Analysis, and Heat Treatment Evaluation

by Guojin Sun, Shengzhi Zhu, Zhenggui Li and Qi Wang

Metals 2024, 14(9), 1083; https://doi.org/10.3390/met14091083 - 21 Sep 2024

Viewed by 682

Abstract

This study investigates the development and characterization of ceramic rod-reinforced TWIP (twinning-induced plasticity) steel matrix composites, produced using the lost foam casting technique. Mechanical tests revealed a substantial improvement in both flexural strength and ductility, with the composite demonstrating more than double the [...] Read more.

This study investigates the development and characterization of ceramic rod-reinforced TWIP (twinning-induced plasticity) steel matrix composites, produced using the lost foam casting technique. Mechanical tests revealed a substantial improvement in both flexural strength and ductility, with the composite demonstrating more than double the strength of unreinforced TWIP steel. Furthermore, a simple low-temperature heat treatment further enhanced these properties, increasing the flexural strength of the composite to 1023 MPa while also improving its ductility. The improvement in mechanical performance is attributed to the formation of additional twins in the TWIP steel matrix during deformation following heat treatment, which resulted in further strengthening of the matrix. Full article

(This article belongs to the Special Issue Plasticity and Metal Forming)

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10 pages, 2063 KiB

Open AccessArticle

Superconductivity in ZrB₁₂ under High Pressure

by Zexiao Zhang, Xu Zheng, Hanshan Luo, Chan Gao, Xiaowei Xue, Jingcheng Zhu, Ruobin Li, Changqing Jin and Xiaohui Yu

Metals 2024, 14(9), 1082; https://doi.org/10.3390/met14091082 - 21 Sep 2024

Viewed by 579

Abstract

Transition metal borides have emerged as pivotal players in various fields. In addition to their exceptional properties such as high hardness, a high melting point, and corrosion resistance, certain compounds exhibit remarkable characteristics including superconductivity, magnetism, electrical conductivity, and catalytic activity. Among these [...] Read more.

Transition metal borides have emerged as pivotal players in various fields. In addition to their exceptional properties such as high hardness, a high melting point, and corrosion resistance, certain compounds exhibit remarkable characteristics including superconductivity, magnetism, electrical conductivity, and catalytic activity. Among these compounds, ZrB₁₂ has garnered significant attention due to its unique physicochemical properties. However, previous research on ZrB₁₂ has predominantly focused on its mechanical behavior while overlooking the electron-electron interactions of the superconducting state. In this paper, resistance characterization of ZrB₁₂ under high-pressure conditions was conducted to further investigate its superconductivity. Our research findings indicate that ZrB₁₂ maintains its superconductivity within a pressure range of 0 to 1.5 GPa and is classified as a type 2 superconductor. Additionally, the results confirm the anisotropic nature of ZrB₁₂’s superconductivity. As the pressure increases, the superconducting transition temperature undergoes a gradual decrease. Remarkably, ZrB₁₂ exhibits metallic behavior under pressures up to 31.4 GPa. The observed decline in superconductivity in ZrB₁₂ can be ascribed to the intensified influence of Zr’s movement on phonon dispersion, ultimately leading to a reduction in carrier concentration. Full article

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66 pages, 14659 KiB

Open AccessReview

Advancements in Metal Processing Additive Technologies: Selective Laser Melting (SLM)

by Neetesh Soni, Gilda Renna and Paola Leo

Metals 2024, 14(9), 1081; https://doi.org/10.3390/met14091081 - 21 Sep 2024

Viewed by 1634

Abstract

Nowadays, the use of metal processing additive technologies is a rapidly growing field in the manufacturing industry. These technologies, such as metal 3D printing (also known as additive manufacturing) and laser cladding, allow for the production of complex geometries and intricate designs that [...] Read more.

Nowadays, the use of metal processing additive technologies is a rapidly growing field in the manufacturing industry. These technologies, such as metal 3D printing (also known as additive manufacturing) and laser cladding, allow for the production of complex geometries and intricate designs that would be impossible with traditional manufacturing methods. They also offer the ability to create parts with customized properties, such as improved strength, wear resistance, and corrosion resistance. In other words, these technologies have the potential to revolutionize the way we design and produce products, reducing costs and increasing efficiency to improve product quality and functionality. One of the significant advantages of these metal processing additive technologies is a reduction in waste and environmental impact. However, there are also some challenges associated with these technologies. One of the main challenges is the cost of equipment and materials, which can be prohibitively expensive for small businesses and individuals. Additionally, the quality of parts produced with these technologies can be affected by factors such as printing speed, temperature, and post-processing methods. This review article aims to contribute to a deep understanding of the processing, properties, and applications of ferrous and non-ferrous alloys in the context of SLM to assist readers in obtaining high-quality AM components. Simultaneously, it emphasizes the importance of further research, optimization, and cost-effective approaches to promote the broader adoption of SLM technology in the industry. Full article

(This article belongs to the Special Issue Advances in 3D Printing Technologies of Metals—2nd Edition)

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9 pages, 1957 KiB

Open AccessArticle

Effective Corrosion Inhibition of Galvanic Corrosion of Cu Coupled to Au by Sodium Dodecyl Sulfate (SDS) and Polyethylene Glycol (PEG) in Acid Solution

by HeeKwon Shin and SeKwon Oh

Metals 2024, 14(9), 1080; https://doi.org/10.3390/met14091080 - 21 Sep 2024

Viewed by 643

Abstract

This study investigates the effects of sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG) on the galvanic corrosion behavior of copper (Cu) coupled to gold (Au) in a printed circuit board (PCB) etching solution. Galvanic corrosion tests using ZRA (zero resistance ammeter) were [...] Read more.

This study investigates the effects of sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG) on the galvanic corrosion behavior of copper (Cu) coupled to gold (Au) in a printed circuit board (PCB) etching solution. Galvanic corrosion tests using ZRA (zero resistance ammeter) were performed to determine the optimal SDS concentration for corrosion inhibition. The corrosion current between Cu and Au decreased significantly with the addition of SDS, from 3.26 mA/cm² to 0.248 mA/cm² at 4 mM SDS, achieving an inhibitor efficiency (IE) of 92.3%. However, at 15 mM SDS, the corrosion current increased, and IE decreased to 80.5%. This phenomenon is attributed to the critical micelle concentration (CMC) of SDS, where surfactant molecules aggregate and reduce surface adsorption properties. Similarly, ZRA tests were conducted to analyze the effects of PEG on galvanic corrosion. The corrosion current significantly decreased with PEG addition, achieving 98.1% IE at 1 g/L and 99.5% IE at 2 g/L. Beyond this concentration, no significant change in IE was observed, indicating saturation. Potentiodynamic polarization tests were also conducted to study the individual effects of SDS and PEG on Cu and Au. The results showed that SDS effectively inhibited Cu corrosion but had a minimal impact on Au. In contrast, PEG significantly reduced the corrosion current density for both Cu and Au, with reductions of 99.5% and 95.1%, respectively. Full article

(This article belongs to the Special Issue Advances in Corrosion and Protection of Materials (Second Edition))

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10 pages, 12271 KiB

Open AccessArticle

Effect of Ball Milling Parameters on Properties of Nano-Sized Tungsten Powder via Mechanochemical Processing

by Feng Li, Guihang Zhang, Pengfei Zheng, Wei Qian, Yaxia Wei, Bingsheng Li, Ming Zhang, Zhijie Zhang and Tong Che

Metals 2024, 14(9), 1079; https://doi.org/10.3390/met14091079 - 20 Sep 2024

Viewed by 716

Abstract

Nano-sized tungsten exhibits superior properties due to its high-density grain boundaries’ strengthening. The high-quality nano-sized powder is essential for sintering nano-sized tungsten bulks through powder metallurgy techniques. In this study, nano-sized tungsten powder was successfully synthesized by mechanochemical methods using mixed WO₃ [...] Read more.

Nano-sized tungsten exhibits superior properties due to its high-density grain boundaries’ strengthening. The high-quality nano-sized powder is essential for sintering nano-sized tungsten bulks through powder metallurgy techniques. In this study, nano-sized tungsten powder was successfully synthesized by mechanochemical methods using mixed WO₃ and Mg powders. The effects of processing parameters on the morphology and microstructure of synthesized powder were thoroughly investigated. The results reveal that the thermite reaction of WO₃ and Mg is almost complete after 5 min of ball milling at a speed of 300 rpm. The average grain size of the tungsten powder decreases with the increasing milling duration and speed. Optimal average grain size and purity were achieved at a milling speed of 300 rpm and a milling duration ranging from 30 to 120 min. Moreover, centrifugation sieving further reduces the average grain size of tungsten powder to 19.5 nm. In addition, the entire mechanochemical process can be divided into two stages: the reaction stage and the grain size refinement stage. Full article

(This article belongs to the Special Issue Powder Metallurgy of Metallic Materials)

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20 pages, 7071 KiB

Open AccessArticle

Effective Removal of Arsenic from Copper Matte by Sodium Carbonate

by Dawei Wang, Jinyao Tang and Yuxia Song

Metals 2024, 14(9), 1078; https://doi.org/10.3390/met14091078 - 19 Sep 2024

Viewed by 453

Abstract

Residual arsenic in copper matte is a source of arsenic contamination in subsequent processes in the smelting section of copper pyrometallurgy. In order to solve the impact of arsenic in copper matte on the subsequent process of smelting, this study removes arsenic from [...] Read more.

Residual arsenic in copper matte is a source of arsenic contamination in subsequent processes in the smelting section of copper pyrometallurgy. In order to solve the impact of arsenic in copper matte on the subsequent process of smelting, this study removes arsenic from copper matte by adding an arsenic removal agent to the molten copper matte. The results show that the most difficult arsenic phase in copper matte is the residual arsenic in copper-arsenic alloys, based on which sodium carbonate was selected as the arsenic removal agent. The arsenic content in the copper matte was reduced by 98% under the optimal experimental conditions of a reaction temperature of 1250 °C, 4% sodium carbonate addition, and a reaction time of 60 min. The experimental results of the reaction mechanism show that sodium carbonate plays two main roles in the process of removing the intractable residual arsenic in copper matte. One is that sodium carbonate has a low melting point, which enhances the fluidity of the reactants. The other is that it can provide oxygen to the reaction system and convert arsenic in the copper-arsenic alloy into gaseous arsenic and arsenate. This study can provide new ideas for controlling arsenic pollution in copper pyrometallurgy. Full article

(This article belongs to the Special Issue Metal Extraction/Refining and Product Development)

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17 pages, 15413 KiB

Open AccessArticle

Kinetics of Iron Collector Leaching in HCl and HF Media

by Evgeniy Kuzas, Ivan Sandalov, Kirill Karimov, Aleksei Kritskii, Ilia Fomenko, Ivan Zhidkov and Aleksandr Abramov

Metals 2024, 14(9), 1077; https://doi.org/10.3390/met14091077 - 19 Sep 2024

Viewed by 784

Abstract

Automotive catalysts containing Platinum Group Metals (PGMs) are valuable secondary raw materials for refineries. Hydrometallurgical processing of catalysts is ineffective due to the low PGMs content—0.15–0.3%. Therefore, such raw materials are melted into an iron collector containing 1.5–5% PGMs. However, when leaching a [...] Read more.

Automotive catalysts containing Platinum Group Metals (PGMs) are valuable secondary raw materials for refineries. Hydrometallurgical processing of catalysts is ineffective due to the low PGMs content—0.15–0.3%. Therefore, such raw materials are melted into an iron collector containing 1.5–5% PGMs. However, when leaching a collector containing 10–20% Si in both HCl and H₂SO₄, the recovery of PGMs does not exceed 40%. The latter indicates incomplete destroying of the PGM-encapsulating ferrosilicon matrix. To completely destroy the ferrosilicon matrix, it is proposed to carry out the leaching process in a mixture of HCl and HF. In this case, the extraction of Fe into solution and Si into the gas phase (in the form of SiF₄) exceeds 90%. This should be sufficient to completely destroy the ferrosilicon matrix and release PGMs. The current work presents the results of studies of the leaching kinetics of the iron collector containing ferrosilicon in a mixture of HCl and HF using the Shrinking Core Model (SCM). It was found that the greatest positive effect on Fe extraction into solution is exerted by HCl concentration and temperature, while Si release into the gas phase is only influenced by HF concentration. In addition, during the destroying of ferrosilicon, FeF₂ is formed and deposited on the surface of the material in the form of thin-film conglomerates. This leads to diffusion difficulties and a gradual decrease in the intensity of the iron collector leaching 30 min after the start of process. After 120 min, there may be a decrease in Fe recovery into solution. Full article

(This article belongs to the Special Issue Separation and Purification of Critical Metals)

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19 pages, 7254 KiB

Open AccessArticle

Designing the Chemical Composition of Steel with Required Hardenability Using Computational Methods

by Neven Tomašić, Wojciech Sitek, Dario Iljkić and Wendimu Fanta Gemechu

Metals 2024, 14(9), 1076; https://doi.org/10.3390/met14091076 - 19 Sep 2024

Viewed by 989

Abstract

This paper introduces an innovative approach that enables the automated and precise prediction of steel’s chemical composition based on the desired Jominy curve. The microstructure, and in fact the presence of martensite, is decisive for the hardness of the steel, so the study [...] Read more.

This paper introduces an innovative approach that enables the automated and precise prediction of steel’s chemical composition based on the desired Jominy curve. The microstructure, and in fact the presence of martensite, is decisive for the hardness of the steel, so the study considered the occurrence of this phase at particular distances from the quenched end of the Jominy sample. Steels for quenching and tempering and case hardening were investigated. With the representative collected dataset of hardness values from the quenched end of the Jominy specimen, microstructure and chemical composition of steels, the complex regression model was made using supervised artificial neural networks. The balance between cost and required hardenability can be achieved through optimizing the chemical composition of steel. This model of designing steel with required hardenability can be of great benefit in the mechanical engineering and manufacturing industry. The model is verified experimentally. Full article

(This article belongs to the Section Computation and Simulation on Metals)

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19 pages, 13271 KiB

Open AccessArticle

Sintering Mechanism and Leaching Kinetics of Low-Grade Mixed Lithium Ore and Limestone

by Wanying Fu, Long Meng and Jingkui Qu

Metals 2024, 14(9), 1075; https://doi.org/10.3390/met14091075 - 19 Sep 2024

Viewed by 735

Abstract

With the rapid development of new energy fields and the current shortage of lithium supply, an efficient, clean, and stable lithium resource extraction process is urgently necessary. In this paper, various advanced detection methods were utilized to conduct a mineralogical analysis of the [...] Read more.

With the rapid development of new energy fields and the current shortage of lithium supply, an efficient, clean, and stable lithium resource extraction process is urgently necessary. In this paper, various advanced detection methods were utilized to conduct a mineralogical analysis of the raw ore and systematically study the occurrence state of lithium; the limestone sintering process was strengthened and optimized, elucidating the sintering mechanism and analyzing the leaching process kinetics. Under an ingredient ratio of 1:3, a sample particle size of 300 mesh, a sintering temperature of 1100 °C, a sintering time of 3 h, a liquid–solid ratio of 2:1, a leaching temperature of 95 °C, and a leaching time of 1 h, the leaching rate of Li reached 90.04%. The highly active Ca–O combined with Si–O on the surface of β–spodumene to CaSiO₄, and Al–O was isolated and combined with Li to LiAlO₂, which was beneficial for the leaching process. The leaching process was controlled by both surface chemical reactions and diffusion processes, and Ea was 27.18 kJ/mol. These studies provide theoretical guidance for the subsequent re-optimization of the process. Full article

(This article belongs to the Special Issue Comprehensive Recycling of Metallurgical Solid Waste and Mineral Resources)

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13 pages, 8237 KiB

Open AccessArticle

The Effects of Microstructure on the Thermophysical Properties of the K439B Ni-Based Superalloy

by Yidong Wu, Jiemin Gao, Xuanjing Zhang, Jiahui Zheng and Xidong Hui

Metals 2024, 14(9), 1074; https://doi.org/10.3390/met14091074 - 19 Sep 2024

Viewed by 835

Abstract

The thermophysical properties of superalloys are critical for the design, fabrication, and service of hot-end components in engines. In this work, the influence of microstructure on the thermophysical parameters including heat conductivity, thermal diffusivity, heat expansion coefficient, and specific heat capacity of the [...] Read more.

The thermophysical properties of superalloys are critical for the design, fabrication, and service of hot-end components in engines. In this work, the influence of microstructure on the thermophysical parameters including heat conductivity, thermal diffusivity, heat expansion coefficient, and specific heat capacity of the K439B superalloy, which is a prospective cast superalloy for engine casings, were investigated from 100 °C to 900 °C. It has been observed that these properties increase with temperature, especially between 700 °C and 800 °C, for alloys subjected to different heat treatment processes. When compared under the same temperature, these parameters decrease with an increase in the size and volume fraction of the γ′ phase in the alloys. Meanwhile, the interfaces between the γ/γ′ phase and the boundaries between dendrites also impeded the heat treatment. It can be concluded that among the alloys with different heat treatment process, the sequence 1160 °C/4 h + 1080 °C/4 h + 845 °C/20 h exhibited the most stable heat conductivity and lowest heat expansion coefficient, making it advantageous for high-temperature service. Full article

(This article belongs to the Special Issue Characterization and Processing Technology of Superalloys)

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13 pages, 7246 KiB

Open AccessArticle

Influence of Ironing Roller on the Wrinkling of a 4N6 Aluminum Foil during the Coiling Process of Cleaning Line

by Xiaogang Zuo and Zhimin Lv

Metals 2024, 14(9), 1073; https://doi.org/10.3390/met14091073 - 19 Sep 2024

Viewed by 542

Abstract

Ironing roll is vital equipment in the production of wide aluminum foil, which has a significant impact on the wrinkling defects of aluminum foil during the winding process of the cleaning production line. In this paper, wrinkling defects in 4N6 aluminum foils were [...] Read more.

Ironing roll is vital equipment in the production of wide aluminum foil, which has a significant impact on the wrinkling defects of aluminum foil during the winding process of the cleaning production line. In this paper, wrinkling defects in 4N6 aluminum foils were improved using the ABAQUS finite element software 2020. A dynamic simulation model of the aluminum foil winding process was established. The ethics model first analyzed the causes of wrinkling during the aluminum foil coiling process. Then the influence of each factor on aluminum foil wrinkling was studied for the effect of ironing pressure, ironing roll deviation, the friction coefficient between the ironing roll and the aluminum foil, and the shape of the ironing roll on the wrinkling of the aluminum foil. The friction coefficients between aluminum foil coils and the uneven distribution of coiling tension have different effects on the wrinkling of aluminum foil. By selecting the optimal process parameters, it is possible to improve the forming quality of the aluminum foil sheet and to reduce the wrinkling faults in the winding process. Full article

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12 pages, 7972 KiB

Open AccessCommunication

Wear-Resistant Boronizing for 17-4PH Components of Fluid Pump

by Yongchao Chen, Guoming Chen, Chang Du and Kang Liu

Metals 2024, 14(9), 1072; https://doi.org/10.3390/met14091072 - 19 Sep 2024

Viewed by 565

Abstract

The fluid pump was the key component of the formation tester; the pump cylinder, piston, and piston rod of the fluid pump often suffer from wear scratches and seal failure, which greatly reduces the service reliability of the instrument. To improve the wear [...] Read more.

The fluid pump was the key component of the formation tester; the pump cylinder, piston, and piston rod of the fluid pump often suffer from wear scratches and seal failure, which greatly reduces the service reliability of the instrument. To improve the wear resistance of the fluid pump, 17-4PH steel specimens were treated by boronizing at 750 °C for 20 h. Specimens with and without boronizing were studied by OM, SEM, XRD, microhardness test, and wear resistance test. Layers of about 60 μm thickness formed during boronization contain a mixture of FeB, CrB, and α(B)-Fe phases, which leads to a significant improvement in microhardness (from 336 to 980 HV) and wear rate (from 16.4 × 10⁻⁵ mm³/Nm to 3.3 × 10⁻⁵ mm³/Nm). The pump cylinder and the fluid-pump piston rod were boronized and assembled into the pumping module, which passed the indoor durability test for 90 h and did not show obvious surface wear after 60 h of field experience. For the first time, the boronization process extends the service time of the fluid pump, improving the wear resistance of the pump cylinder and piston rod. Full article

(This article belongs to the Section Corrosion and Protection)

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17 pages, 8133 KiB

Open AccessArticle

Effect of Surface Treatment on Tensile Strength of Steel Single Lap Joints Bonded with Double-Sided Acrylic Foam Tapes for Naval Applications

by Guido Di Bella, Mohamed Chairi, Antonio Denaro and Adriano Bado

Metals 2024, 14(9), 1071; https://doi.org/10.3390/met14091071 - 18 Sep 2024

Viewed by 591

Abstract

This study investigated single lap joints in steel used for naval carpentry. The surface was mechanically treated, and then a double-sided acrylic foam tape was applied with varying surface preparation conditions. Specifically, three different conditions were examined. Tensile tests revealed that changing the [...] Read more.

This study investigated single lap joints in steel used for naval carpentry. The surface was mechanically treated, and then a double-sided acrylic foam tape was applied with varying surface preparation conditions. Specifically, three different conditions were examined. Tensile tests revealed that changing the type of surface preparation significantly affects the mechanical strength of the joints. The best mechanical properties were achieved when a primer was used. Our results demonstrate that this method can be effectively employed in naval applications as an alternative to welding for non-structural applications, such as the installation of brackets for mounting electrical devices (e.g., sockets). Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: “Welding and Joining”)

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12 pages, 7313 KiB

Open AccessArticle

Morphological Characteristics of W/Cu Composite Nanoparticles with Complex Phase Structure Synthesized via Reactive Radio Frequency (RF) Thermal Plasma

by Chulwoong Han, Song-Yi Kim, Soobin Kim and Ji-Woon Lee

Metals 2024, 14(9), 1070; https://doi.org/10.3390/met14091070 - 18 Sep 2024

Viewed by 535

Abstract

The W/Cu binary system is characterized by its mutual insolubility and excellent wettability, making W/Cu composite materials ideal for managing thermal and electrical properties in electronic components. To optimize material properties, control over the microstructure is crucial, and nanocomposites with uniform dispersion offer [...] Read more.

The W/Cu binary system is characterized by its mutual insolubility and excellent wettability, making W/Cu composite materials ideal for managing thermal and electrical properties in electronic components. To optimize material properties, control over the microstructure is crucial, and nanocomposites with uniform dispersion offer significant advantages. In this study, W/Cu composite nanoparticles were synthesized by feeding a blended feedstock of tungsten trioxide (WO₃) micro-powder and cupric oxide (CuO) micro-powder into a reactive radio frequency (RF) argon–hydrogen thermal plasma system. Cu-coated W nanocomposite particles were obtained through the vaporization, reduction, and condensation processes. The resulting nanocomposite particles were composed of body-centered cubic (BCC) α-W, A15 β-W, and face-centered cubic (FCC) Cu phases, with a chemical composition closely matching theoretical calculations. The phase evolution and morphological changes of the synthesized particles were analyzed as a function of heat treatment temperatures up to 1000 °C in a reducing atmosphere. Up to 600 °C, the phase composition and morphology remained stable. At 800 °C, localized diffusion and coalescence of Cu led to the formation of particulate Cu, and a significant phase transformation from metastable β-W to α-W was observed. Additionally, extensive Cu segregation due to long-range diffusion resulted in distinct Cu-rich and Cu-depleted regions. In these regions, notable sintering of W particles and the complete disappearance of β-W occurred. The results showed that the temperature-dependent redistribution of Cu plays a crucial role in the phase transformation of W and the morphology of W/Cu composite particles. Full article

(This article belongs to the Section Metallic Functional Materials)

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16 pages, 4367 KiB

Open AccessArticle

A Method of Images to Study Plate-Impact-Induced Cavitation in Aluminum through Molecular Dynamics Simulation

by Yingzhen Jiang, Ziyang Ma, Haijian Chu and Huiling Duan

Metals 2024, 14(9), 1069; https://doi.org/10.3390/met14091069 - 18 Sep 2024

Viewed by 454

Abstract

The tensile stress generated by the superposition of two reflection waves in the target plays a critical role in explaining plate-impact-induced spalling. A method of images is proposed to simulate the physical process of wave superposition and this method is applied in order [...] Read more.

The tensile stress generated by the superposition of two reflection waves in the target plays a critical role in explaining plate-impact-induced spalling. A method of images is proposed to simulate the physical process of wave superposition and this method is applied in order to study the cavitation mechanism in single-crystal Al through molecular dynamics simulation. The critical impact-load velocity for the cavitation obtained by this method is as small as 400 m/s, which is much lower than the result (650 m/s) obtained by the conventional piston-load method. The new cavitation mechanism found is distinctively different from the conventional dislocation-entanglement-induced cavitation under high-velocity impact. The new mechanism involves two key events: firstly, a crack-like defect is formed and its relevant atomic bonds are broken under high tensile stress, resulting in a great momentum of related atoms; and secondly, previous high-momentum atoms collide with the atoms in their running way, resulting in the destruction of the original FCC structure locally and nanovoids or penny-shaped voids being formed. Additionally, the cavitation region, the number of voids, and delamination surfaces increases with the impact-load rate. Full article

(This article belongs to the Section Crystallography and Applications of Metallic Materials)

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18 pages, 14311 KiB

Open AccessArticle

Research on Process Characteristics and Properties in Deep-Penetration Variable-Polarity Tungsten Inert Gas Welding of AA7075 Aluminum Alloy

by Zheng Peng, Ying Liang, Hongbing Liu, Fei Wang, Jin Yang and Yanbo Song

Metals 2024, 14(9), 1068; https://doi.org/10.3390/met14091068 - 18 Sep 2024

Viewed by 525

Abstract

In this study, a new deep-penetration variable-polarity tungsten inert gas (DP-VPTIG) welding process, which is performed by a triple-frequency-modulated pulse, was employed in the welding fabrication of 8 mm AA7075 aluminum plates. The electric signal, arc shape, and weld pool morphology of the [...] Read more.

In this study, a new deep-penetration variable-polarity tungsten inert gas (DP-VPTIG) welding process, which is performed by a triple-frequency-modulated pulse, was employed in the welding fabrication of 8 mm AA7075 aluminum plates. The electric signal, arc shape, and weld pool morphology of the welding process were obtained by means of high-speed photography and an electric signal acquisition system under varying parameters of the intermediate frequency (IF) pulse current. The principle of the arc characteristics and the dynamic mechanism of the weld melting during the process are explained. In addition, the macroforming, microstructure, and microhardness of the welded joints were investigated. The results indicate that, with an intermediate frequency pulse of 750 Hz, the arc displayed a higher energy density and a more effective arc contraction, which improved weld appearance and penetration. Moreover, the impact and stirring action of the arc refined the microstructure grains of the weld center. Therefore, this new welding method is feasible for welding medium-thickness aluminum alloy plates without a groove. Full article

(This article belongs to the Section Welding and Joining)

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17 pages, 10684 KiB

Open AccessArticle

Alternatives to Reduce Hot Cracking Susceptibility of IN718 Casting Alloy Laser Beam Welds with a Mushroom Shape

by Leire García-Sesma, Pedro Álvarez, Eider Gorostegui-Colinas, I. Huarte and Fernando Santos

Metals 2024, 14(9), 1067; https://doi.org/10.3390/met14091067 - 18 Sep 2024

Viewed by 819

Abstract

Reducing hot cracking is essential for ensuring seamless production of nickel superalloys, which are extensively used in welded structures for aircraft engines. The prevalence of hot cracking in precipitation-strengthened alloy 718 is primarily governed by two factors: firstly, the chemical composition and the [...] Read more.

Reducing hot cracking is essential for ensuring seamless production of nickel superalloys, which are extensively used in welded structures for aircraft engines. The prevalence of hot cracking in precipitation-strengthened alloy 718 is primarily governed by two factors: firstly, the chemical composition and the coarse microstructure formed during solidification, and secondly, the activation of hot cracking mechanisms, which is particularly critical in mushroom-shaped welding morphologies. In this study, different nickel-based superalloys welded using laser beam welding (LBW), more specifically bead on plate welding (BoP), specimens are compared. The cracking susceptibility of both wrought and two investment casting 718 alloys with tailored chemical compositions is examined through the application of both continuous and pulsed LBW. Additionally, various pre-weld treatments, including with and without Pre-HIP (hot isostatic pressing), are analyzed. The influences of chemical composition, LBW parameters and pre- and post-welding treatments on both internal and external cracks determined by conventional and advanced non-destructive tests are studied. A clear reduction of hot cracking susceptibility and overall welding quality improvement was observed in a tailored 718 alloy with relatively high Ni (55.6% wt) and Co (1.11% wt) contents. Full article

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21 pages, 387 KiB

Open AccessArticle

New Method to Recover Activation Energy: Application to Copper Oxidation

by Dominique Barchiesi and Thomas Grosges

Metals 2024, 14(9), 1066; https://doi.org/10.3390/met14091066 - 18 Sep 2024

Viewed by 582

Abstract

The calculation of the activation energy helps to understand and to identify the underlying phenomenon of oxidation. We propose a new method without any a priori hypothesis on the oxidation law, to retrieve the activation energy of partially and totally oxidized samples subject [...] Read more.

The calculation of the activation energy helps to understand and to identify the underlying phenomenon of oxidation. We propose a new method without any a priori hypothesis on the oxidation law, to retrieve the activation energy of partially and totally oxidized samples subject to successive annealing. The method handles the uncertainties on the measurement of metal and oxide thicknesses, at the beginning and at the end of the annealing process. The possible change in oxidation law during annealing is included in the model. By using an adapted Particle Swarm Optimization method to solve the inverse problem, we also calculate the time of final oxidation during the last annealing. We apply the method to successive annealings of three samples with initial nanometric layers of copper, at ambient pressure, in the open air. One, two and three successive laws are recovered from experimental data. We found activation energy values about 105–108 kJ

{mol}^{- 1}

at the beginning of the oxidation, 76–87 kJ

{mol}^{- 1}

at the second step, and finally 47–59 kJ

{mol}^{- 1}

in a third step. We also show that the time evolution of copper and oxide thicknesses can also be retrieved with their uncertainties. Full article

(This article belongs to the Special Issue Metallic Nanostructured Materials and Thin Films)

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23 pages, 7411 KiB

Open AccessReview

Improvement of High Temperature Wear Resistance of Laser-Cladding High-Entropy Alloy Coatings: A Review

by Yantao Han and Hanguang Fu

Metals 2024, 14(9), 1065; https://doi.org/10.3390/met14091065 - 18 Sep 2024

Viewed by 1719

Abstract

As a novel type of metal material emerging in recent years, high-entropy alloy boasts properties such as a simplified microstructure, high strength, high hardness and wear resistance. High-entropy alloys can use laser cladding to produce coatings that exhibit excellent metallurgical bonding with the [...] Read more.

As a novel type of metal material emerging in recent years, high-entropy alloy boasts properties such as a simplified microstructure, high strength, high hardness and wear resistance. High-entropy alloys can use laser cladding to produce coatings that exhibit excellent metallurgical bonding with the substrate, thereby significantly improvement of the wear resistance of the material surface. In this paper, the research progress on improving the high-temperature wear resistance of high entropy alloy coatings (LC-HEACs) was mainly analyzed based on the effect of some added alloying elements and the presence of hard ceramic phases. Building on this foundation, the study primarily examines the impact of adding elements such as aluminum, titanium, copper, silicon, and molybdenum, along with hard ceramic particles like TiC, WC, and NbC, on the phase structure of coatings, high-temperature mechanisms, and the synergistic interactions between these elements. Additionally, it explores the potential of promising lubricating particles and introduces an innovative, highly efficient additive manufacturing technology known as extreme high-speed laser metal deposition (EHLMD). Finally, this paper summarizes the main difficulties involved in increasing the high-temperature wear resistance of LC-HEACs and some problems worthy of attention in the future development. Full article

(This article belongs to the Special Issue Surface Engineering and Coating Tribology—2nd Edition)

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14 pages, 5698 KiB

Open AccessArticle

Understanding the High-Temperature Deformation Behaviors in Additively Manufactured Al6061+TiC Composites via In Situ Neutron Diffraction

by Minglei Qu, Dunji Yu, Lianyi Chen, Ke An and Yan Chen

Metals 2024, 14(9), 1064; https://doi.org/10.3390/met14091064 - 17 Sep 2024

Viewed by 912

Abstract

Aluminum matrix composites (AMCs) are designed to enhance the performance of conventional aluminum alloys for engineering applications at both room and elevated temperatures. However, the dynamic phase-specific deformation behavior and load-sharing mechanisms of AMCs at elevated temperatures have not been extensively studied and [...] Read more.

Aluminum matrix composites (AMCs) are designed to enhance the performance of conventional aluminum alloys for engineering applications at both room and elevated temperatures. However, the dynamic phase-specific deformation behavior and load-sharing mechanisms of AMCs at elevated temperatures have not been extensively studied and remain unclear. Here, in situ neutron diffraction experiments are employed to reveal the phase-specific structure evolution of additively manufactured Al6061+TiC composites under compressive loading at 250 °C. It is found that the addition of a small amount of nano-size TiC significantly alters the deformation behavior and increases the strength at 250 °C in comparison to the as-printed Al6061. Unlike the two-stage behavior observed in Al6061, the Al6061+TiC composites exhibit three stages during compression triggered by changes in the interphase stress states. Further analysis of Bragg peak intensity and broadening reveals that the presence of TiC alters the dislocation activity during deformation at 250 °C by influencing dislocation slip planes and promoting dislocation accumulation. These findings provide direct experimental observations of the phase-specific dynamic process in AMCs under deformation at an elevated temperature. The revealed mechanisms provide insights for the future design and optimization of high-performance AMCs. Full article

(This article belongs to the Special Issue Advances in Preparation Methods and Numerical Simulation of Composites: Formation and Properties)

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16 pages, 15466 KiB

Open AccessArticle

Research on Pre-Compensation and Shape-Control Optimization of Hemming Structures with Dissimilar Materials Based on Forming Process Chain

by Jianjun Li, Qin Sun, Jia Jia and Wenfeng Zhu

Metals 2024, 14(9), 1063; https://doi.org/10.3390/met14091063 - 17 Sep 2024

Viewed by 745

Abstract

The steel–aluminum hybrid body closure panels can achieve a more balanced and lightweight performance. However, the differences in the physical properties of metal sheets and the complex changes in the properties of the adhesive material result in cumulative deviations in the composite-forming process. [...] Read more.

The steel–aluminum hybrid body closure panels can achieve a more balanced and lightweight performance. However, the differences in the physical properties of metal sheets and the complex changes in the properties of the adhesive material result in cumulative deviations in the composite-forming process. This paper proposes a deformation pre-compensation modeling method for the autobody closure panels hemming system oriented towards the process chain, in response to the problem that single-process optimization cannot obtain global optimal results. Taking the car door scaled model as an example, based on surface reconstruction and node compensation, the curing deformation amount is fed back in advance to the gluing and hemming processes. The deformation deviation is corrected through geometric parameter pre-compensation to achieve overall process shape control and optimization. Research shows that this method can significantly reduce the surface differences and gaps of hemming structures with dissimilar materials, and a single iteration can reduce the assembly surface difference by more than 90%. This provides a reference for improving the manufacturing quality of steel–aluminum hybrid body closure panels. Full article

(This article belongs to the Section Welding and Joining)

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