Metals

21 pages, 8410 KiB

Open AccessArticle

Effect of Extrusion Temperature on the Microstructure and Properties of Biomedical Mg-1Zn-0.4Ca-1MgO Composite

by Shuaipeng Gao, Shaoyuan Lyu, Qian Zhao and Minfang Chen

Metals 2025, 15(3), 337; https://doi.org/10.3390/met15030337 - 20 Mar 2025

Cited by 1 | Viewed by 198

The effects of extrusion temperatures on the microstructure, mechanical properties, and corrosion performance of biomedical Mg-1Zn-0.4Ca-1MgO composites were systematically investigated. The results indicated that lower extrusion temperatures notably refined the grain size and promoted the formation of numerous nano-scaled secondary phase particles. The [...] Read more.

The effects of extrusion temperatures on the microstructure, mechanical properties, and corrosion performance of biomedical Mg-1Zn-0.4Ca-1MgO composites were systematically investigated. The results indicated that lower extrusion temperatures notably refined the grain size and promoted the formation of numerous nano-scaled secondary phase particles. The grain sizes were 0.8 μm, 1.7 μm, and 3.4 μm for the materials extruded at 280 °C, 310 °C, and 330 °C, which were named ET280, ET310, and ET330. The finest grain size and abundant precipitates enhanced the mechanical properties of the composite with a microhardness of 86.9 HV, a yield strength of 305 MPa, and a fracture elongation of 15.2%. Moreover, the ET280 alloy with ultra-fine grains exhibited the optimal corrosion resistance among these three composites, and its annual corrosion after immersion in Hank’s solution for 14 days was only 0.17 mm/y. The excellent performance in vitro immersion was mainly attributed to the formation of the uniformly dense Ca-P layer on its surface and the contiguous compact Mg(OH)₂ layer, which could effectively weaken the contact between the corrosive solution and the Mg matrix. Full article

(This article belongs to the Special Issue Metal Composite Materials and Their Interface Behavior)

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15 pages, 7363 KiB

Open AccessArticle

The Effect of Heat Treatment and Cold Forging on the Mechanical Properties of SCr420 Low-Alloy Steel

by Jaehan Lim, Soonhong Hwang, Sangwon Lee and Byounglok Jang

Metals 2025, 15(3), 336; https://doi.org/10.3390/met15030336 - 19 Mar 2025

Viewed by 199

Abstract

This study developed a new heat treatment method, normalizing and stress relief (NSR), to increase productivity compared to spheroidizing annealing (SA). The influence of different microstructures resulting from these heat treatments was investigated in cold-forged steel. Despite a shorter heat treatment time, the [...] Read more.

This study developed a new heat treatment method, normalizing and stress relief (NSR), to increase productivity compared to spheroidizing annealing (SA). The influence of different microstructures resulting from these heat treatments was investigated in cold-forged steel. Despite a shorter heat treatment time, the mechanical properties of the NSR alloy were found to be similar to those of the SA alloy. The factors influencing the mechanical properties of the experimental alloys were analyzed using the Hall–Petch equation, and the predicted values closely matched the measured strength of hyper-eutectoid steels. The primary factors affecting mechanical properties were microstructure and dislocation density. In the case of the SA alloy, the microstructure was associated with lower strength due to the spherical cementite structure. In contrast, the NSR alloy had lower strength because of a reduced dislocation density. This was achieved via stress-relief heat treatment below the A₁ temperature after phase transformation. Based on the mechanical properties, cold forging simulations showed that the effective stress during cold forging of the NSR alloy was similar to that of the SA alloy. Full article

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17 pages, 31445 KiB

Open AccessArticle

Damping and Compressive Properties of SLM-Fabricated Rhombic Dodecahedron-Structured Ni–Ti Shape Memory Alloy Foams

by Di Guo, Qingzhou Wang, Li Liu, Shuo Liu, Hao Cao, Jingxia Xie and Fuxing Yin

Metals 2025, 15(3), 335; https://doi.org/10.3390/met15030335 - 19 Mar 2025

Viewed by 173

Abstract

Ni–Ti shape memory alloy (SMA) foams, capable of bringing revolutionary changes to crucial fields such as aerospace, energy engineering, and biomedical applications, are at the forefront of materials science research. With the aim of designing Ni–Ti SMA foams with complex structures, near-equiatomic Ni–Ti [...] Read more.

Ni–Ti shape memory alloy (SMA) foams, capable of bringing revolutionary changes to crucial fields such as aerospace, energy engineering, and biomedical applications, are at the forefront of materials science research. With the aim of designing Ni–Ti SMA foams with complex structures, near-equiatomic Ni–Ti SMA foams featuring a rhombic dodecahedron (RD) structure were fabricated using selective laser melting (SLM) technology. Damping, superelasticity, and quasi-static compressive mechanical tests were carried out on the resultant foams. The findings indicated that the smaller the unit structure of the RD or the larger the rod diameter, the higher the damping and compressive strength of the foams would be. Foams with a cell structure of 2 mm × 2 mm × 2 mm and a rod diameter of 0.6 mm exhibited the highest damping, reaching up to 0.049, along with the highest compressive strength, reaching up to 145 MPa. Furthermore, if the specimen underwent solution and aging heat treatments, its strength could be further enhanced. Meanwhile, the specimens also exhibited excellent superelasticity; even when the pre-strain was 6%, the elastic recovery could still reach 97%. Based on microstructure characterization and finite element simulation, the property mechanisms and deformation rules of the foams were revealed. Full article

(This article belongs to the Special Issue Porous Metallic Materials: Properties, Applications and Latest Research Progress)

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21 pages, 34817 KiB

Open AccessArticle

Hot Deformation Behaviors and Dynamic Softening Mechanisms of As-Cast XM-19 Super Austenitic Stainless Steel

by Lujun Cao, Yucheng Zhou, Liujie Xu and Yuanhang Sun

Metals 2025, 15(3), 334; https://doi.org/10.3390/met15030334 - 19 Mar 2025

Viewed by 179

Abstract

The hot deformation behaviors and dynamic softening mechanisms of XM-19 super austenitic stainless steel (SASS) were investigated using the isothermal compression test in the temperature range from 1025 to 1250 °C and a compression rate of 0.01–10 s⁻¹. A hot processing [...] Read more.

The hot deformation behaviors and dynamic softening mechanisms of XM-19 super austenitic stainless steel (SASS) were investigated using the isothermal compression test in the temperature range from 1025 to 1250 °C and a compression rate of 0.01–10 s⁻¹. A hot processing map with a strain of 0.9 was constructed, and the analysis results show that the optimal thermal deformation parameters are a temperature range of 1200–1250 °C and a strain rate range of 0.03–0.2 s⁻¹. The thermal activation energy at 0.7 strain is calculated to be 614.3 kJ/mol by developing constitutive equations under various deformation parameters, which is essentially higher than the range of thermal deformation activation energy of typical austenitic stainless steels. At a high temperature of 1250 °C, the synergistic effect of adiabatic heating and increased dislocation density drives the recrystallization fraction to surge from 20% to 78% as the strain rate rises from 0.01 to 10 s⁻¹, while at a fixed strain rate of 0.1 s⁻¹, the increase in deformation temperature from 1025 °C to 1250 °C promotes dynamic recrystallization (DRX), leading to a parallel rise in recrystallization fraction to 25%. The nucleation mechanism of XM-19 SASS is primarily driven by discontinuous dynamic recrystallization (DDRX), with a supporting role of continuous dynamic recrystallization (CDRX). The contribution of CDRX decreases gradually with increasing deformation temperature. Full article

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19 pages, 5333 KiB

Open AccessArticle

Structural Integrity and Life Assessment of Ti-6Al-4V Orthopaedic Implants

by Katarina Čolić, Svetlana M. Kostić, Simon Sedmak, Nenad Gubeljak and Aleksandar Grbović

Metals 2025, 15(3), 333; https://doi.org/10.3390/met15030333 - 19 Mar 2025

Viewed by 281

Abstract

This paper presents an experimental and numerical analysis of the mechanical behaviour of orthopaedic implants with crack-type defects, considering the principles and advantages of the modern X-FEM method, which was used due to limitations of traditional FEM in terms of crack growth simulation, [...] Read more.

This paper presents an experimental and numerical analysis of the mechanical behaviour of orthopaedic implants with crack-type defects, considering the principles and advantages of the modern X-FEM method, which was used due to limitations of traditional FEM in terms of crack growth simulation, especially for complex geometries. In X-FEM, the finite element space is enriched with discontinuity functions and asymptotic functions at the crack tip, which are integrated into the standard finite element approximation using the unity division property. Though rare, femoral component failures are well-documented complications that can occur after hip prosthetic implantation. Most stem fractures happen in the first third of the implant due to the loosening of the proximal stem and fixation of the distal stem, leading to bending and eventual fatigue failure. The main goal of this paper was to obtain accurate and representative models of such failures. Experimental analyses of the mechanical behaviour of implants subjected to physiological loads, according to relevant standards, using a new combined approach, including both experiments and numerical simulations was presented. The goal was to verify the numerical results and obtain a novel, effective methodology for assessing the remaining fatigue life of hip implants. For this purpose, the analysis of the influence of Paris coefficients on the total number of cycles was also considered. Hence, this simulation involved defining loads to closely mimic real-life scenarios, including a combination of activities such as ascending stairs, stumbling, and descending stairs. The tensile properties of the titanium alloy were experimentally determined, along with the Paris law coefficients C and m. The finite element software ANSYS 2022R2 version was used to develop and calculate the three-dimensional model with a crack, and the resulting stresses, stress intensity factors, and the number of cycles presented in the figures, tables, and diagrams. The results for the fatigue life of a partial hip implant subjected to various load cases indicated significant differences in behaviour, and this underscores the importance of analysing each case individually, as these loads are heavily influenced by each patient’s specific activities. It was concluded that the use of numerical methods enabled the preliminary analyses of the mechanical behaviour of implants under fatigue loading for several different load cases, and these findings can be effectively used to predict the possibility of Ti-6Al-4V implant failure under variable cyclic loads. Full article

(This article belongs to the Special Issue Structural Integrity of Lightweight Alloys)

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12 pages, 2794 KiB

Open AccessArticle

Electrochemical Characterization of Aluminum Alloy AlSi10Mg(Fe) for Its Potential Application as End Plate Material in Fuel Cells

by Darshita Pranlal Chhaniyara, Marcel Mandel and Lutz Krüger

Metals 2025, 15(3), 332; https://doi.org/10.3390/met15030332 - 19 Mar 2025

Viewed by 291

Abstract

End plates are important multi-functional components of the fuel cells. They provide structural support and are responsible for channeling the reactant gases, by-product water, and fuel cell coolant in and out of the fuel cell stack. Among various materials used for end plates, [...] Read more.

End plates are important multi-functional components of the fuel cells. They provide structural support and are responsible for channeling the reactant gases, by-product water, and fuel cell coolant in and out of the fuel cell stack. Among various materials used for end plates, aluminum alloy is used due to its high strength and low density. But its corrosion resistance depends on the environment. The operating fuel cell conditions may cause the fuel cell coolant to become more acidic or basic in nature and thus can lead to corrosion of end plates. In this work, a common die-cast aluminum alloy, AlSi10Mg(Fe), is used for end plates, and its corrosion behavior in direct contact with the fuel cell coolant is analyzed. The electrochemical characterization of uncoated and anodized aluminum alloy was achieved using electrochemical impedance spectroscopy, potentiodynamic and potentiostatic polarization tests at room temperature and at the operating temperature of the fuel cell at 80 °C. It was found that for the uncoated aluminum alloy, the corrosion sensitivity is slightly increased when the temperature increases. In comparison, the anodized aluminum alloy reveals a decrease in corrosion sensitivity after 100 h of potentiostatic control, indicating an ongoing passivation of the surface due to the formation of aluminum oxides/hydroxides and aluminum alcohol corrosion products. Full article

(This article belongs to the Special Issue Manufacture, Properties and Applications of Light Alloys)

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16 pages, 12925 KiB

Open AccessArticle

Influence of Friction Stir Processing Post-Treatment on the Microstructure and Mechanical Properties of 205A Aluminum Alloy Produced by Wire Arc-Directed Energy Deposition

by Jing Ma, Siyue Fan, Yuqi Gong, Qingwei Jiang and Fei Li

Metals 2025, 15(3), 331; https://doi.org/10.3390/met15030331 - 19 Mar 2025

Viewed by 278

Abstract

Although wire arc-directed energy deposition (WA-DED) technology demonstrates advancements in the rapid manufacturing of high-strength Al-Cu aluminum alloy components, coarse microstructures and pore defects inhibit its further development and application. In this study, friction stir processing (FSP) post-treatment was employed to improve the [...] Read more.

Although wire arc-directed energy deposition (WA-DED) technology demonstrates advancements in the rapid manufacturing of high-strength Al-Cu aluminum alloy components, coarse microstructures and pore defects inhibit its further development and application. In this study, friction stir processing (FSP) post-treatment was employed to improve the microstructure and mechanical properties of the 205A aluminum alloy component produced by WA-DED, and the effects of rotational rate on the microstructure and properties were also investigated. Key findings showed that the average grain size of the as-deposited sample was significantly refined from 22.8 μm to less than 5 μm after FSP post-treatment, and most of the pore defects were eliminated. Most of the α-Al + θ-Al₂Cu eutectic structures distributed on the grain boundaries were dissolved into the α-Al matrix after FSP post-treatment, and the element segregation phenomenon was effectively improved. The microhardness of the stirred zone significantly increased due to the microstructure refinement and pore elimination. The excellent elongation of the component was obtained after FSP post-treatment using a relatively low rotational rate of 800 min⁻¹. Comparatively, after improving the rotational rate to 1200 min⁻¹, the strength of the component slightly increased with the reduction in elongation. Compared to the as-deposited sample, the average yield strength, ultimate tensile strength, and elongation increased by 32.7%, 20.6% and 56.7%, respectively. Full article

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

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21 pages, 18023 KiB

Open AccessArticle

Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching

by Pavel Grudinsky, Ekaterina Vasileva and Valery Dyubanov

Metals 2025, 15(3), 330; https://doi.org/10.3390/met15030330 - 18 Mar 2025

Viewed by 190

Abstract

Copper-bearing Waelz slag (CBWS) is a solid by-product of the Waelz process, the disposal of which faces significant environmental challenges. In this study, oxidative sulfuric acid leaching was applied for the recovery of valuable elements from a CBWS sample containing 26.23% Fe, 0.82% [...] Read more.

Copper-bearing Waelz slag (CBWS) is a solid by-product of the Waelz process, the disposal of which faces significant environmental challenges. In this study, oxidative sulfuric acid leaching was applied for the recovery of valuable elements from a CBWS sample containing 26.23% Fe, 0.82% Cu, and 0.81% Zn. Experimental leaching was conducted at temperature ranges, durations, and solid-to-liquid (S/L) ratios of 25–90 °C, 5–240 min, and 0.05–0.5 g/cm³, respectively. The consumption rates of H₂SO₄ and H₂O₂ ranged within 9.18–15.29 mmol/g and 0–7.35 mmol/g, which, at a 1:4:1 g/cm³/cm³ ratio, were equal to 225–375 g/dm³ H₂SO₄ and 0–250 g/dm³ H₂O₂, respectively. Various oxidants such as H₂O₂, MnO₂, air, oxygen, and Fe³⁺ ions were tested in the leaching experiments. The optimal leaching conditions were proven to be a temperature of 70 °C, duration of 180 min, S/L ratio of 0.2 g/cm³, and consumption rate of 13.4 mmol H₂SO₄/g. These leaching conditions led to the recovery of 96.1% Fe, 87.0% Cu, and 86.9% Zn with the addition of 2.94 mmol H₂O₂/g and 95.2% Fe, 84.7% Cu, and 67.5% Zn with the addition of 0.095 g MnO₂/g. These results suggest that metallic iron particles contained in a CBWS sample complicate copper dissolution. Full article

(This article belongs to the Special Issue Separation, Purification and Extraction of Metals from Primary and Secondary Resources)

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15 pages, 3182 KiB

Open AccessArticle

Ab Initio Investigation of the Stability, Electronic, Mechanical, and Transport Properties of New Double Half Heusler Alloys Ti₂Pt₂ZSb (Z = Al, Ga, In)

by Nurgul S. Soltanbek, Nurpeiis A. Merali, Nursultan E. Sagatov, Fatima U. Abuova, Edgars Elsts, Aisulu U. Abuova, Vladimir V. Khovaylo, Talgat M. Inerbaev, Marina Konuhova and Anatoli I. Popov

Metals 2025, 15(3), 329; https://doi.org/10.3390/met15030329 - 18 Mar 2025

Viewed by 229

Abstract

This research aimed to explore the structural, electronic, mechanical, and vibrational properties of double half Heusler compounds with the generic formula Ti₂Pt₂ZSb (Z = Al, Ga, and In), using density functional theory calculations. The generalized gradient approximation within the [...] Read more.

This research aimed to explore the structural, electronic, mechanical, and vibrational properties of double half Heusler compounds with the generic formula Ti₂Pt₂ZSb (Z = Al, Ga, and In), using density functional theory calculations. The generalized gradient approximation within the PBE functional was employed for structural relaxation and for calculations of vibrational and mechanical properties and thermal conductivity, while the hybrid HSE06 functional was employed for calculations of the electronic properties. Our results demonstrate that these compounds are energetically favorable and dynamically and mechanically stable. Our electronic structure calculations revealed that the Ti₂Pt₂AlSb double half Heusler compound is a non-magnetic semiconductor with an indirect band gap of 1.49 eV, while Ti₂Pt₂GaSb and Ti₂Pt₂InSb are non-magnetic semiconductors with direct band gaps of 1.40 eV. Further analysis, including phonon dispersion curves, the electron localization function (ELF), and Bader charge analysis, provided insights into the bonding character and vibrational properties of these materials. These findings suggest that double half Heusler compounds are promising candidates for thermoelectric device applications and energy-conversion devices, due to their favorable properties. Full article

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19 pages, 7528 KiB

Open AccessArticle

A Finite Element Analysis Framework for Assessing the Structural Integrity of Aero-Engine Ceramic Matrix Composite Component Coatings

by Giacomo Canale, Vitantonio Esperto and Felice Rubino

Metals 2025, 15(3), 328; https://doi.org/10.3390/met15030328 - 18 Mar 2025

Viewed by 271

Abstract

Ceramic Matrix Composites (CMCs), and, in particular, SiC/BN/SiC, are currently being investigated to replace Nickel alloys in the manufacturing of aero-engine high-pressure turbine system components. Although superior to traditional metallic solutions in terms of resistance to high temperatures, CMCs are prone to oxidation [...] Read more.

Ceramic Matrix Composites (CMCs), and, in particular, SiC/BN/SiC, are currently being investigated to replace Nickel alloys in the manufacturing of aero-engine high-pressure turbine system components. Although superior to traditional metallic solutions in terms of resistance to high temperatures, CMCs are prone to oxidation and environmental degradation. For this reason, a multi-layer coating system is used to protect the CMC substrate. The aim of this paper is to define a Finite Element (FE) thermo-mechanical procedure to assess the integrity of the multi-layer coating. Among the four main failure mechanisms, vertical transverse cracking (denoted as “mud cracking”) and the thermally grown oxide (TGO) formation were numerically investigated. The FE (Finite Elements) procedure described in this paper, fully automated with the auxilium of MATLAB and Abaqus, is holistic and offers a simplified tool for the preliminary lifing of coating systems. TGO growth in the bond layer leads to the failure of the coating after 15,200 h, when its thickness reaches 0.02 mm, circa 20% of the bond layer (BND), and the stiffness and the strength of the BND drop to zero. The procedures and outcomes from the work are relevant for aero-engine designers and system engineers. Full article

(This article belongs to the Special Issue Surface Modification and Coatings of Metallic Materials)

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17 pages, 10068 KiB

Open AccessArticle

Corrosion Behavior of Al-Mg Alloys with Different Alloying Element Contents in 3.5% NaCl Solution

by Weitao Zhou, Fei Xue and Moucheng Li

Metals 2025, 15(3), 327; https://doi.org/10.3390/met15030327 - 18 Mar 2025

Cited by 1 | Viewed by 321

Abstract

The corrosion behavior was investigated for three Al-Mg aluminum alloys (i.e., 5052, 5083 and 5182 aluminum alloys) with different alloying contents in 3.5 wt.% NaCl solution at 35 °C by means of potentiodynamic polarization, electrochemical impedance spectroscopy, immersion test, X-ray photoelectron spectroscopy and [...] Read more.

The corrosion behavior was investigated for three Al-Mg aluminum alloys (i.e., 5052, 5083 and 5182 aluminum alloys) with different alloying contents in 3.5 wt.% NaCl solution at 35 °C by means of potentiodynamic polarization, electrochemical impedance spectroscopy, immersion test, X-ray photoelectron spectroscopy and microscopy techniques. All alloys spontaneously passivate in the test solution, but the pitting corrosion takes place at the intermetallic phases during the long-term immersion test. The comparative analyses indicate that more Mg and less Cr in aluminum alloys result in increases in the passive current density and the pit depth and decreases in the polarization resistance, the pitting potential and the ratio of Al₂O₃/Al(OH)₃ in the product film. However, the differences in the pitting potentials of the three aluminum alloys are smaller than approximately 22 mV. Their pit depth values are less than 110 μm after 120 days of immersion. The three aluminum alloys have relatively high corrosion resistance in the simulated seawater solution. Full article

(This article belongs to the Special Issue Corrosion of Metals: Behaviors and Mechanisms)

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41 pages, 6573 KiB

Open AccessReview

Research and Development Progress of Laser–Arc Hybrid Welding: A Review

by Yang He, Xinyu Song, Zhidong Yang, Ruihai Duan, Jiangmin Xu, Wenqin Wang, Liangyu Chen, Mingxiao Shi and Shujin Chen

Metals 2025, 15(3), 326; https://doi.org/10.3390/met15030326 - 17 Mar 2025

Viewed by 458

Abstract

Laser–arc hybrid welding (LAHW) is an advanced welding technology that integrates both laser and arc heat sources within a single molten pool, achieving synergistic benefits that surpass the sum of their individual contributions. This method enhances the welding speed and depth of the [...] Read more.

Laser–arc hybrid welding (LAHW) is an advanced welding technology that integrates both laser and arc heat sources within a single molten pool, achieving synergistic benefits that surpass the sum of their individual contributions. This method enhances the welding speed and depth of the fusion, stabilizes the process, and minimizes welding defects. Numerous studies have investigated the principles, synergistic effects, keyhole dynamics, joint performance, and various factors influencing the parameters of laser–arc hybrid welding. This paper begins with an introduction to the classification of LAHW, followed by a discussion of the characteristics of gas-shielded welding, argon arc welding, and plasma hybrid welding. Subsequently, the welding principles underlying laser–arc hybrid welding will be elucidated. To enhance weld integrity and quality, this paper will analyze keyhole behavior, droplet transfer dynamics, welding quality performance, and the generation and prevention of welding defects that affect laser–arc hybrid welding. Additionally, a detailed analysis of the effects of residual stress on the shape, microstructure, and phase composition of the weld will be provided, along with an exploration of the influences of various welding parameters on post-weld deformation and mechanical properties. Full article

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19 pages, 10178 KiB

Open AccessArticle

Optimization of Laser Welding Parameters and Fixed Stress Span Design to Minimize Deformation in Ultra-Thin Ferritic Stainless Steel

by Jinlong Su, Jingyi Li, Kaining Zhu, Fei Xing, Xiaoming Qiu and Jingwei Liang

Metals 2025, 15(3), 325; https://doi.org/10.3390/met15030325 - 17 Mar 2025

Viewed by 251

Abstract

Ultra-thin ferritic stainless steel, essential for applications such as proton exchange membrane fuel cells, presents challenges during pulsed laser welding due to thermal stresses causing deformation. This study explores the effects of welding parameters and clamp design on deformation through finite element simulations [...] Read more.

Ultra-thin ferritic stainless steel, essential for applications such as proton exchange membrane fuel cells, presents challenges during pulsed laser welding due to thermal stresses causing deformation. This study explores the effects of welding parameters and clamp design on deformation through finite element simulations and experiments. Key parameters, including laser power (500–700 W), welding speed (6–14 mm/s), and pulse frequency (6–14 Hz), were systematically varied. Results revealed a non-linear relationship between these parameters and weld quality, with the optimal combination identified as a laser power of 600 W, welding speed of 10 mm/s, and pulse frequency of 10 Hz. Additionally, the fixed stress span applied by clamps significantly influenced stress–strain and displacement fields. For instance, residual stress decreased from 267 MPa at a 5 mm span to 189 MPa at a 20 mm span. Displacement values increased from 4.746 × 10⁻³ mm at 5 mm to 8.111 × 10⁻³ mm at 20 mm, while strain initially decreased but rose slightly from 1.648 × 10⁻³ at 10 mm to 1.719 × 10⁻³ at 15 mm. The 5 mm stress span was found optimal, producing a smooth and defect-free weld surface. This study bridges gaps in understanding the deformation mechanics of ultra-thin ferritic stainless steel, offering practical guidelines for optimizing laser welding parameters and clamp designs to achieve superior weld quality. Full article

(This article belongs to the Section Welding and Joining)

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18 pages, 4080 KiB

Open AccessArticle

A Feature Extraction Algorithm for Corner Cracks in Slabs Based on Multi-Scale Adaptive Gradient Descent

by Kai Zeng, Zibo Xia, Junlei Qian, Xueqiang Du, Pengcheng Xiao and Liguang Zhu

Metals 2025, 15(3), 324; https://doi.org/10.3390/met15030324 - 17 Mar 2025

Viewed by 209

Abstract

Cracks at the corners of casting billets have a small morphology and rough surfaces. Corner cracks are generally irregular, with a depth of about 0.2–5 mm and a width of about 0.5–3 mm. It is difficult to detect the depth of cracks and [...] Read more.

Cracks at the corners of casting billets have a small morphology and rough surfaces. Corner cracks are generally irregular, with a depth of about 0.2–5 mm and a width of about 0.5–3 mm. It is difficult to detect the depth of cracks and the three-dimensional morphological characteristics. The severity of cracks is hard to evaluate with traditional inspection methods. To effectively extract the topographic features of corner cracks, a multi-scale surface crack feature extraction algorithm, based on weighted adaptive gradient descent, was proposed. Firstly, the point cloud data of the corners of the billet were collected by the three-dimensional visual inspection platform. The point cloud neighborhood density was calculated using the k-nearest neighbor method; then the weighted covariance matrix was used to calculate the normal rate of change. Secondly, the adaptive attenuation rate, based on normal change, was fused with the density weight, which can calculate the Gaussian weight in regard to the neighborhood. Gaussian weights were used to obtain the gradient changes between point clouds to acquire the multi-scale morphological features of the crack. Finally, the interference caused by surface and boundary effects was eliminated by DBSCAN density clustering. The complete three-dimensional morphology characteristics of the crack were obtained. The experimental results reveal that the precision rate, recall rate, and F-value of the improved algorithm are 96.68%, 91.32%, and 93.92%, respectively, which are superior to the results from the RANSAC and other mainstream algorithms. The three-dimensional morphological characteristics of corner cracks can be effectively extracted using the improved algorithm, which provides a basis for judging the severity of the defect. Full article

(This article belongs to the Special Issue Casting Process, Processing Deformation and Microstructure Optimization of Advanced Metallic Materials)

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18 pages, 11893 KiB

Open AccessArticle

Mechanical Properties Simulation of Aluminum Alloy Sheet Using SSP and CPFEM

by Wei Wang, Ting Li, Guobin Wang, François Luneau and Manuel Henner

Metals 2025, 15(3), 323; https://doi.org/10.3390/met15030323 - 15 Mar 2025

Viewed by 409

Abstract

This paper focuses on the mechanical performance of an aluminum alloy with uneven microstructure formed after stamping and brazing. The mechanical behavior of the stamping area is studied through the crystal plasticity finite element method (CPFEM). Firstly, the crystal plastic parameters of the [...] Read more.

This paper focuses on the mechanical performance of an aluminum alloy with uneven microstructure formed after stamping and brazing. The mechanical behavior of the stamping area is studied through the crystal plasticity finite element method (CPFEM). Firstly, the crystal plastic parameters of the material are obtained by fitting the experimental and simulated results of nanoindentation. Then, a polycrystalline tensile model is established using a Step-by-Step Packing method, with orientation distribution assigned based on EBSD results, followed by polycrystalline tensile simulations using CPFEM. The results demonstrate that CPFEM can effectively simulate the mechanical behavior of the studied aluminum alloy. Additionally, the study reveals significant orientation-dependent mechanical responses. Full article

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15 pages, 10124 KiB

Open AccessArticle

Study on Slag Phase Control of Thermal Reduction of Spodumene

by Xuefeng Liu, Mingliang Yang, Yuncheng Zhong, Shichao Wang, Tao Qu and Yong Deng

Metals 2025, 15(3), 322; https://doi.org/10.3390/met15030322 - 15 Mar 2025

Viewed by 324

Abstract

Aiming at the problems of low utilization rate of spodumene resources and serious environmental pollution, our team proposes a clean process to produce manganese-silicon alloy for lithium enrichment by carbothermal reduction of spodumene. In this process, the melting point and viscosity of the [...] Read more.

Aiming at the problems of low utilization rate of spodumene resources and serious environmental pollution, our team proposes a clean process to produce manganese-silicon alloy for lithium enrichment by carbothermal reduction of spodumene. In this process, the melting point and viscosity of the slag phase are very high, which affects the slag discharge and slag–metal separation. Therefore, this experiment considers the addition of CaO as a slagging agent based on the previous process and tests and analyzes the slag phase under different CaO contents. When the CaO content is 30%, the slag phase is mainly Ca₂Al₂SiO₇; the reduction rate of lithium is 99.02%; the direct yield of the alloy is 89.12%; and the melting point of the slag is 1260 °C. It can melt and wrap the alloy before removing the alloy, which has heat preservation and oxidation resistance. The viscosity of the slag at 1360 °C is 0.11 Pa·s, which is within the optimum viscosity range of the slag in actual industrial production. Experiments show that the addition of CaO is beneficial to the removal of lithium and the separation of slag and metal, which lays a good foundation for the industrialization development of the previous process and improves the economic benefits of the whole process. Full article

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14 pages, 6295 KiB

Open AccessArticle

The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy

by Honghui Lin, Xuetao Ke, Guangxin Xiong, Binqing Shi, Zhengrong Zhang and Chuanqiang Li

Metals 2025, 15(3), 321; https://doi.org/10.3390/met15030321 - 15 Mar 2025

Viewed by 390

Abstract

The body-centered cubic (BCC)-structured magnesium–lithium (Mg-Li) alloy is the lightest metal material, but its mechanical properties are poor, especially its strength. In this study, the effect of adding rare earth Y on the microstructure and mechanical properties of as-cast BCC Mg-11Li-6Zn-xY (x = [...] Read more.

The body-centered cubic (BCC)-structured magnesium–lithium (Mg-Li) alloy is the lightest metal material, but its mechanical properties are poor, especially its strength. In this study, the effect of adding rare earth Y on the microstructure and mechanical properties of as-cast BCC Mg-11Li-6Zn-xY (x = 0, 0.5, 1.2, and 2, in wt.%) alloys was investigated. The results revealed that massive amounts of nano-scale θ (MgLiZn) and/or θ’ (MgLi₂Zn) precipitated inside the grains, and some θ phases precipitated at the grain boundaries in the Mg-11Li-6Zn alloy. With the addition of Y, W phases formed at the grain boundary, their content gradually increased with the Y concentration, and the grain size decreased simultaneously. The Mg-11Li-6Zn-0.5Y alloy exhibited higher ultimate tensile strength (190 MPa) and elongation (27%) at room temperature than those (170 MPa and 22%) of the Mg-11Li-6Zn alloy, presenting improvements of 11.8% and 22.7% in strength and ductility, respectively. The improvements in the mechanical properties of the Mg-11Li-6Zn alloy achieved by adding less Y could be attributed to the formation of moderate W phases and a reduction in grain size. However, once the addition of Y became excessive, the mechanical properties of the Mg-11Li-6Zn-1.2Y alloy were reduced due to the formation of too many reticular W phases. In addition, the Mg-11Li-6Zn-2Y alloy containing the highest Y content had the lowest ultimate tensile strength, 163 MPa, and highest ductility, 38%, due to the combined effect of the most reticular W phases and the smallest grains. Furthermore, the fracture morphology of the Mg-11Li-6Zn alloy displayed apparent necking, which became insignificant after the addition of Y, indicating that this addition could improve its uniform plastic deformation ability. Full article

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20 pages, 2470 KiB

Open AccessReview

Improving the Clinical Performance of Dental Implants Through Advanced Surface Treatments: The Case of Ti and ZrO₂ Coatings

by Mohamed Aissi, Qanita Tayyaba, Azzedine Er-Ramly, Hendra Hermawan and Nadia Merzouk

Metals 2025, 15(3), 320; https://doi.org/10.3390/met15030320 - 14 Mar 2025

Viewed by 440

Abstract

This review summarizes the development of surface treatments applied to dental implants with the aim of improving their clinical performance. It covers the advancement of various techniques, from the conventional to the more advanced ones. Among the recent advancements, surface texturing has enabled [...] Read more.

This review summarizes the development of surface treatments applied to dental implants with the aim of improving their clinical performance. It covers the advancement of various techniques, from the conventional to the more advanced ones. Among the recent advancements, surface texturing has enabled atomic and structural modifications of implant surfaces at the micro- and nanoscales, improving tissue–material interactions. Acid etching and atomic layer deposition applied onto implant surfaces results in optimized osseointegration by stimulating the deposition and proliferation of osteoblasts and fibroblasts. The atomic layer deposition of TiO₂, ZnO, ZrO₂, and CaCO₃ has proven effective in improving osseointegration and tackling corrosion. Corrosion is still an important issue, whereby metals released from titanium implants and their associated degradation products cause local and systemic side effects, leaving a wide avenue for future research. The development of hybrid dental implants is envisaged through new materials and technologies, such as additive manufacturing, which may play a critical role in the fabrication of patient-specific implants with tailored nano-topography capable of enhancing such properties as antibacterial activity and osseointegration. Full article

(This article belongs to the Special Issue Advanced Biomedical Materials (2nd Edition))

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31 pages, 9481 KiB

Open AccessArticle

Electrochemical and Tribological Behavior of Dual-Phase Steels Obtained from a Commercial-Grade API 5CT Steel

by C. Guerra-Linares, M. J. Soria-Aguilar, J. García-Guerra, A. Martínez-Luevanos, F. R. Carrillo-Pedroza, E. Gutíerrez-Castañeda, J. C. Díaz-Guillén, J. L. Acevedo Dávila and J. M. González de la Cruz

Metals 2025, 15(3), 319; https://doi.org/10.3390/met15030319 - 14 Mar 2025

Viewed by 370

Abstract

In this study, the effect of martensite volume fraction on the mechanical, tribological, and corrosion properties of API 5CT dual-phase steel is studied based on intercritical heat treatment routes at different temperatures (730, 760, and 790 °C). Hardness of the specimens increased by [...] Read more.

In this study, the effect of martensite volume fraction on the mechanical, tribological, and corrosion properties of API 5CT dual-phase steel is studied based on intercritical heat treatment routes at different temperatures (730, 760, and 790 °C). Hardness of the specimens increased by increasing the martensite volume fraction up to 50%. Further increase in martensite volume fraction led to an increase in wear resistance. Sliding wear pin-on-disk tests were analyzed following the ASTM G99 standard, obtaining the wear rate, the volume of lost mass, and the Archard coefficient as a function of time and temperature of the heat treatment. A comparison was made between the wear rate and the hardness data, and its proportionality was established. The corrosion behavior of DP steels in 3.5% NaCl solution was studied by the potentiodynamic polarization technique. The result showed that with increasing the martensite amount in the specimen and decreasing the ferrite amount, the corrosion rate decreased. Finally, the corrosion mechanism in DP steel depends on the self-corrosion resistance behavior of both phases (martensite-ferrite) as well as the presence of galvanic corrosion between them. Full article

(This article belongs to the Topic Microstructure and Properties in Metals and Alloys, 3rd Volume)

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21 pages, 2204 KiB

Open AccessArticle

Enhanced Three-Stage Cluster-Then-Classify Method (ETSCCM)

by Duygu Yilmaz Eroglu and Elif Guleryuz

Metals 2025, 15(3), 318; https://doi.org/10.3390/met15030318 - 14 Mar 2025

Viewed by 312

Abstract

Modern steel manufacturing processes demand rigorous quality control to rapidly and accurately detect and classify defects in steel plates. In this work, we propose an enhanced three-stage cluster-then-classify method (ETSCCM) that merges clustering-based data partitioning with strategic feature subset selection and refined hyperparameter [...] Read more.

Modern steel manufacturing processes demand rigorous quality control to rapidly and accurately detect and classify defects in steel plates. In this work, we propose an enhanced three-stage cluster-then-classify method (ETSCCM) that merges clustering-based data partitioning with strategic feature subset selection and refined hyperparameter tuning. Initially, the appropriate number of clusters is determined by combining K-means with hierarchical clustering, ensuring a more precise segmentation of the Steel Plates Fault dataset. Concurrently, various correlated feature subsets are assessed to identify those that maximize classification performance. The best-performing scenario is then used in conjunction with the most effective classifier, identified through comparative analyses involving widely adopted algorithms. Experimental outcomes on real-world fault data, as well as additional publicly available datasets, indicate that our approach can achieve a significant increase in prediction accuracy compared to conventional methods. This study introduces a new method by jointly refining cluster assignments and classification parameters through scenario-based feature subsets, going beyond single-stage methods in enhancing detection accuracy. Through this multi-stage process, pivotal data relationships are uncovered, resulting in a robust, adaptable framework that advances industrial fault diagnosis. Full article

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13 pages, 6400 KiB

Open AccessArticle

Optimization of Electrical Conductivity and Hardness in Al-1Si Alloy Through Mg/Fe Alloying and Heat Treatment

by Xiaoli Cui, Houyun Liu, Yan Wang, Chao Lu, Wenqing Shi and Di Tie

Metals 2025, 15(3), 317; https://doi.org/10.3390/met15030317 - 14 Mar 2025

Viewed by 341

Abstract

In this study, a new kind of the Al-1Si-0.6Mg-0.2Fe alloy was fabricated by Mg, Fe alloying treatment and the influence mechanism of Mg, Fe on electrical conductivity (EC) and Vickers hardness (HV) of the Al-1Si alloy was analyzed by the combination of experiments [...] Read more.

In this study, a new kind of the Al-1Si-0.6Mg-0.2Fe alloy was fabricated by Mg, Fe alloying treatment and the influence mechanism of Mg, Fe on electrical conductivity (EC) and Vickers hardness (HV) of the Al-1Si alloy was analyzed by the combination of experiments and simulations. Results showed that during the solidification process, intermediate phase Al₈FeMg₃Si₆ formed which can inhibit the growth of needle-like AlFeSi phase, resulting in a more refined distribution of AlFeSi particles and this is helpful to improve EC and HV simultaneously. According to the simulation results, Al-1Si-0.6Mg-0.2Fe generated the most Al₈FeMg₃Si₆ and the corresponding EC and HV reached 48.5% IACS and 62.9 HV, respectively. Furthermore, during heat treatment process, AlFeSi can promote the nucleation of Mg₂Si, reducing the elemental solution of Mg and Si. With 550 °C/2 h + 210 °C/24 h heat treatment, on the one hand, oversized needle-shaped AlFeSi fused to smaller particles and distributed more uniformly. On the other hand, more solid solution Si and Mg precipitated with form of Mg₂Si. Finally, the EC and HV of Al-1Si-0.6Mg-0.2Fe improved to 54.5% IACS and 79.8 HV, achieving the simultaneous optimization of EC and HV. This can provide theoretical guidance for the preparation of high strength and high conductivity aluminum alloy. Full article

(This article belongs to the Special Issue Special and Short Processes of Aluminum Alloys)

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22 pages, 19071 KiB

Open AccessArticle

Assessment of Rate-Dependency and Adiabatic Heating on the Essential Work of Fracture of Press-Hardening Steels

by Simon Jonsson, David Frómeta, Laura Grifé, Fredrik Larsson and Jörgen Kajberg

Metals 2025, 15(3), 316; https://doi.org/10.3390/met15030316 - 13 Mar 2025

Cited by 1 | Viewed by 492

Abstract

The automotive industry is currently in a paradigm shift transferring the fleet over from internal combustion vehicles to battery electric vehicles (BEV). This introduces new challenges when designing the body-in-white (BIW) due to the sensitive and energy-dense battery that needs to be protected [...] Read more.

The automotive industry is currently in a paradigm shift transferring the fleet over from internal combustion vehicles to battery electric vehicles (BEV). This introduces new challenges when designing the body-in-white (BIW) due to the sensitive and energy-dense battery that needs to be protected in a crash scenario. Press-hardening steels (PHS) have emerged as an excellent choice when designing crash safety parts due to their ability to be manufactured to complex parts with ultra-high strength. It is, however, crucial to evaluate the crash performance of the selected materials before producing parts. Component testing is cumbersome and expensive, often geometry dependent, and it is difficult to separate the bulk material behaviour from other influences such as spot welds. Fracture toughness measured using the essential work of fracture method is a material property which has shown to be able to rationalise crash resistance of advanced high-strength steel (AHSS) grades and is thereby an interesting parameter in classifying steel grades for automotive applications. However, most of the published studies have been performed at quasi-static loading rates, which are vastly different from the strain rates involved in a crash. These higher strain rates may also lead to adiabatic self-heating which might influence the fracture toughness of the material. In this work, two PHS grades, high strength and very high strength, intended for automotive applications were investigated at lower and higher strain rates to determine the rate-dependence on the conventional tensile properties as well as the fracture toughness. Both PHS grades showed a small increase in conventional mechanical properties with increasing strain rate, while only the high-strength PHS grade showed a significant increase in fracture toughness with increasing loading rate. The adiabatic heating in the fracture process zone was estimated with a high-speed thermal camera showing a significant temperature increase up to 300 °C. Full article

(This article belongs to the Special Issue Novel Insights into Hot Sheet Metal Forming of High-Performance Materials)

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26 pages, 5250 KiB

Open AccessArticle

Predicting Fatigue Life of 51CrV4 Steel Parabolic Leaf Springs Manufactured by Hot-Forming and Heat Treatment: A Mean Stress Probabilistic Modeling Approach

by Vítor M. G. Gomes, Miguel A. V. de Figueiredo, José A. F. O. Correia and Abílio M. P. de Jesus

Metals 2025, 15(3), 315; https://doi.org/10.3390/met15030315 - 13 Mar 2025

Viewed by 324

Abstract

The longevity of railway vehicles is an important factor in their mechanical and structural design. Fatigue is a major issue that affects the durability of railway components, and, therefore, knowledge of the fatigue resistance characteristics of critical components, such as leaf springs, must [...] Read more.

The longevity of railway vehicles is an important factor in their mechanical and structural design. Fatigue is a major issue that affects the durability of railway components, and, therefore, knowledge of the fatigue resistance characteristics of critical components, such as leaf springs, must be extensively investigated. This research covers the fatigue resistance of 51CrV4 steel under bending and axial tension, for distinct stress ratios, in the low-cycle fatigue regime (LCF), high-cycle fatigue regime (HCF), and very high-cycle fatigue regime (VHCF) using experimental data collected in this work and from previous experiments. Two fatigue models were analyzed: the Walker model (WSN) and the Castillo–Fernández–Cantelli model, CFC, adapted for the presence of mean stress (ACFC). According to the analysis carried out, both fatigue resistance prediction models provided good results for the experimental data, with the ACFC model showing good fitting when considering all the failure data and outliers. Additionally, fracture surfaces showed a higher trend for crack initiation on the surface for positive stress ratios despite internal defects also possibly being responsible for some fatigue failures. This investigation aimed to provide a probabilistic fatigue model encompassing the LCF, HCF, and VHCF fatigue regimes for distinct stress ratios for the fatigue design analysis of 51CrV4 steel parabolic leaf springs manufactured by hot-forming processes with subsequent heat treatments. Full article

(This article belongs to the Special Issue Numerical and Experimental Advances in Metal Processing)

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14 pages, 7676 KiB

Open AccessArticle

Effect of Solution and Aging Treatment on the Microstructure and Properties of LAZ931 Mg-Li Alloy by Friction Stir Processing

by Zhe Fang, Shuaiwei Xu, Zhixin Wang and Yufeng Sun

Metals 2025, 15(3), 314; https://doi.org/10.3390/met15030314 - 13 Mar 2025

Cited by 1 | Viewed by 352

Abstract

Heat treatment processes play a pivotal role in optimizing the microstructure and mechanical properties of Mg-Li alloys, thereby enhancing their performance and expanding their potential applications in structural and lightweight engineering fields. In this study, the influence of solution and aging treatments on [...] Read more.

Heat treatment processes play a pivotal role in optimizing the microstructure and mechanical properties of Mg-Li alloys, thereby enhancing their performance and expanding their potential applications in structural and lightweight engineering fields. In this study, the influence of solution and aging treatments on the microstructure, phase transformation, and microhardness of friction-stir-processed (FSPed) LAZ931 Mg-Li alloy was investigated to obtain the optimal solution treatment temperature and time. An optimal solution treatment at 460 °C for 0.5 h under an Ar gas atmosphere facilitated complete α-phase dissolution with subsequent aging at 125 °C, triggering precipitation-mediated hardening. An X-ray diffraction (XRD) analysis identified a new MgLi₂Al phase in the stirring zone (SZ) in addition to the α, β, and AlLi phases. Aging kinetics at 125 °C showed that SZ hardness increased to 110.5 HV after solution treatment, which was 5.3% higher than the base metal (BM). After 3 h of aging, microhardness peaked at 86.5 HV before decreasing due to the decomposition of the metastable MgLi₂Al phase into the stable AlLi phase. The microhardness stabilized at around 78 HV, which was 16.2% higher than that of the original SZ. These experimental results provide a fundamental understanding of property structure for meeting the growing demand for lightweight materials and improving material properties. Full article

(This article belongs to the Special Issue Advances in Welding Processes of Metallic Materials)

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17 pages, 10108 KiB

Open AccessArticle

Impact of Novel Nozzles on Atomization Flow Field and Particle Features: Simulation and Experimental Validation

by Kai Wang, Zhongliang Zhou, Wenhai Sun, Yanhui Zhang, Suode Zhang and Jianqiang Wang

Metals 2025, 15(3), 313; https://doi.org/10.3390/met15030313 - 13 Mar 2025

Viewed by 345

Abstract

Gas-atomized powder characteristics significantly impact additive manufacturing processes. Two innovative nozzles, semi-converging–diverging nozzle type II and fully converging–diverging nozzle type III, were designed based on the traditional cylindrical nozzle type I. Utilizing the k-ε model and Discrete Phase Model (DPM), the flow field [...] Read more.

Gas-atomized powder characteristics significantly impact additive manufacturing processes. Two innovative nozzles, semi-converging–diverging nozzle type II and fully converging–diverging nozzle type III, were designed based on the traditional cylindrical nozzle type I. Utilizing the k-ε model and Discrete Phase Model (DPM), the flow field evolution and powder characteristics of these nozzles were analyzed at gas pressures ranging from 4 to 8 MPa. The results indicate that in the gas-phase flow field both nozzle type II and nozzle type III can achieve a performance comparable to that of nozzle type I at significantly lower gas pressures. Specifically, nozzle type II operates effectively with a reduction of approximately 1 MPa compared to nozzle type I, while nozzle type III demonstrates an even greater advantage with a pressure reduction of about 2 MPa. In the gas–melt-phase flow field, nozzle type III still has the effect of reducing the pressure by approximately 2 MPa compared to nozzle type I. The melt fracture process under nozzle type III is divided into three distinct stages: the formation of large droplets, a transition area for fragmentation, and a fully fragmented region. This research effectively reduces energy losses and offers novel insights as well as recommendations for applications related to atomization technology. Full article

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16 pages, 9704 KiB

Open AccessArticle

Research on the Microstructure and Properties of QT400-18 Laser Cladding Remanufacturing

by Jiakai Yan, Peng Dong, Hongxia Zhang, Xujing Niu, Chen Liang and Kewei Li

Metals 2025, 15(3), 312; https://doi.org/10.3390/met15030312 - 13 Mar 2025

Viewed by 351

Abstract

To address the failure issue of local wear in QT400-18 transition shafts used in high-speed trains, laser cladding remanufacturing of a ductile cast iron surface was carried out using 45 wt.%Fe + 55 wt.% Inconel625 powder. The phase composition, microhardness, interfacial bonding strength, [...] Read more.

To address the failure issue of local wear in QT400-18 transition shafts used in high-speed trains, laser cladding remanufacturing of a ductile cast iron surface was carried out using 45 wt.%Fe + 55 wt.% Inconel625 powder. The phase composition, microhardness, interfacial bonding strength, and wear resistance of the cladding layer were analyzed. The results show that the cladding layer is primarily composed of a γ (Ni, Fe) solid solution and a small amount of eutectic carbides. The microstructure of the cladding layer forms columnar dendrites, cellular dendrites, and equiaxed crystals from bottom to top. The microstructure of the single-layer, single-pass interface consists of ferrite, acicular martensite, and ledeburite, while the multi-layer, multi-pass interface consists of ferrite, granular pearlite, and discontinuous ledeburite. The average microhardness of the single-layer, single-pass cladding layer is approximately 350 HV_0.5, and the hardness of the fine-grained and coarse-grained regions of the multi-layer, multi-pass cladding layer is approximately 330 HV_0.5 and 250 HV_0.5, respectively. The interfacial bonding strength reaches 96.5% of the base material strength. The wear mechanism of the cladding layer is mainly mild abrasive wear, with significantly better wear resistance than the base material. Full article

(This article belongs to the Special Issue Development of Metallic Material Laser Additive Manufacturing)

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14 pages, 4787 KiB

Open AccessArticle

Study on Contact Characteristics of Cold Rolled Deformation Zone of Ultra-High-Strength Steel

by Jianhui Wang, Zhenhua Bai, Yuan Gao, Zhourun Shi, Zifei Guo and Xuetong Li

Metals 2025, 15(3), 311; https://doi.org/10.3390/met15030311 - 13 Mar 2025

Viewed by 398

Abstract

This study investigates the longitudinal deformation behavior of ultra-high-strength steel (UHSS) during the cold rolling process. First, rolling experiments were conducted on UHSS, and longitudinal surface coordinates of the deformation zone were collected using a probe-type profiler to obtain the actual profile. The [...] Read more.

This study investigates the longitudinal deformation behavior of ultra-high-strength steel (UHSS) during the cold rolling process. First, rolling experiments were conducted on UHSS, and longitudinal surface coordinates of the deformation zone were collected using a probe-type profiler to obtain the actual profile. The forward slip value was derived from production data. An elastic–plastic finite element model of the UHSS rolling process was then established using the nonlinear finite element method. The model calculated the contact arc shape and forward slip within the deformation zone, with errors of less than 15% for the contour and 10% for forward slip. The model was further used to analyze the impact of rolling parameters on contact profile, stress, and forward slip. The results indicate that reducing plate thickness and tension, along with increasing depression and yield strength, promotes the formation of a neutral zone in the deformation zone. The peak contact stress is linked to increased elastic compression of the rolls and the expansion of the roll exit. Additionally, increases in roll diameter, friction coefficient, and yield strength lead to a gradual increase in forward slip in the deformation zone. Full article

(This article belongs to the Special Issue Plastic and Plastic Processing of Metallic Materials)

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25 pages, 13527 KiB

Open AccessArticle

Achieving High Strength and Plasticity by Controlling the Volume Fractions of Martensite and Ferrite in Rare Earth, Micro-Alloyed Dual-Phase Steel

by Zhishen Li, Xinli Song, Jin Yu, Wei Geng, Xuewen You and Juan Jia

Metals 2025, 15(3), 310; https://doi.org/10.3390/met15030310 - 13 Mar 2025

Viewed by 493

Abstract

The volume fractions of martensite and ferrite in dual-phase steel affect its strength and plasticity. In this study, the effect of heat treatment on the structure morphology and volume fractions of martensitic and ferrite was studied in rare earth, micro-alloyed dual-phase steel, and [...] Read more.

The volume fractions of martensite and ferrite in dual-phase steel affect its strength and plasticity. In this study, the effect of heat treatment on the structure morphology and volume fractions of martensitic and ferrite was studied in rare earth, micro-alloyed dual-phase steel, and the strain-hardening behaviour of the experimental steel under various process conditions was determined. The results show that a uniform structure with an alternating distribution of ferrite and martensite could be obtained by complete quenching before critical annealing, and the martensitic phase content increased from 60% to 93% with a rise in annealing temperature. With the growth in the martensitic phase content, the strength of dual-phase (DP) steel gradually increased, and elongation gradually decreased. However, the strength–plasticity product remained at approximately 17 GPa∙%, showing good comprehensive mechanical properties, and the mechanical properties were better at 780 and 820 °C annealing temperatures. When the martensite content was higher, the strain-hardening ability of the DP steel was stronger. The results show that the failure mode of the DP steel was a typical ductile fracture, and only a small amount of cleavage pattern was observed in the samples annealed at 840 °C. No obvious interfacial disbonding was seen in the tensile fracture, and only a few cracks formed. By optimizing the heat treatment process, the microstructural uniformity was improved, and the ferrite phase was strengthened to some extent, which better coordinated the deformation of ferrite and martensite, thereby delaying fracture. The modification effect of rare earth elements on inclusions in the DP steel was obvious. Full article

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13 pages, 9377 KiB

Open AccessArticle

Wear Resistance of WC-10Co-4Cr Cemented Carbide Coatings Prepared by Atmospheric Plasma Spraying and Laser Cladding

by Zhanji Geng, Feng Liu and Yuping Wang

Metals 2025, 15(3), 309; https://doi.org/10.3390/met15030309 - 12 Mar 2025

Viewed by 400

Abstract

This paper adopts an atmospheric plasma spraying and laser cladding process to prepare WC-10Co-4Cr cemented carbide coatings on the substrate surfaces of 304 stainless steel and 316 stainless steel, respectively, and comparatively analyzes the microstructures, phase compositions, average hardness, and friction and wear [...] Read more.

This paper adopts an atmospheric plasma spraying and laser cladding process to prepare WC-10Co-4Cr cemented carbide coatings on the substrate surfaces of 304 stainless steel and 316 stainless steel, respectively, and comparatively analyzes the microstructures, phase compositions, average hardness, and friction and wear performances of the coatings prepared under the two processes. The analysis showed that the plasma sprayed coating showed a lamellar structure, and the interface between the coating and the substrate was mechanically occluded, while the laser melting coating showed a dendritic structure, and the interface between the coating and the substrate was metallurgically bonded. After decarburization of the plasma sprayed coatings, the W2C phase dominated, while the laser cladding coatings were still dominated by the WC phase. In addition, the average microhardness, coefficient of friction, and mass loss of the plasma sprayed coatings were about 1341.7 HV, 0.45, and 0.005 g, respectively, while those of the laser cladding coatings were about 1440.5 HV, 0.4, and 0.002 g. The overall performance of the laser cladding coatings was better than that of the plasma sprayed coatings. The quality of the prepared WC-10Co-4Cr coatings was improved, which provides guidance for the preparation of WC-10Co-4Cr coatings by laser melting. Full article

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20 pages, 3438 KiB

Open AccessArticle

Microstructural Characterization and Mechanical Properties of AA5083/Coal Composites Fabricated by Friction Stir Processing

by Oritonda Muribwathoho, Velaphi Msomi and Sipokazi Mabuwa

Metals 2025, 15(3), 308; https://doi.org/10.3390/met15030308 - 12 Mar 2025

Viewed by 466

Abstract

This study evaluates the development and characterization of AA5083/Coal composite joints using Friction Stir Processing (FSP) technology. The primary findings reveal significant improvements in the grain structure, with the utilization of FSP leading to an average mean grain size of 31.173 μm, representing [...] Read more.

This study evaluates the development and characterization of AA5083/Coal composite joints using Friction Stir Processing (FSP) technology. The primary findings reveal significant improvements in the grain structure, with the utilization of FSP leading to an average mean grain size of 31.173 μm, representing a reduction of 50.8598% compared to the AA5083-H111 base material. This grain refinement contributed to a notable increase in hardness, achieving an average of 91.42 HV for the AA5083/Coal composite. The highest tensile strength recorded was 280 MPa, with a yield strength of 225.6 MPa. Additionally, flexural strength analysis indicated a significant difference between face and root specimens, with face specimens demonstrating a maximum ultimate flexural strength of 747.53 MPa. However, the agglomeration of coal particles and non-uniform particle distribution negatively impacted the mechanical properties, resulting in a slight reduction in the ultimate tensile strength compared to the AA5083-H111 base material. This work offers valuable insights into the fabrication and characterization of AA5083/Coal composite joints, contributing to the development of lightweight and cost-effective materials. The study underscores the importance of optimizing process parameters to minimize defects and enhance mechanical performance. Full article

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Metals, Volume 15, Issue 3 (March 2025) – 114 articles

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