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18 pages, 16964 KB

Open AccessArticle

Tailoring Microstructure and Mechanical Properties of the Al-7Si-0.35Mg-0.35Fe Alloy by Cr Addition: A Study on Fe-Rich Phase Modification

by Chiteng Le, Wenjun Liu, Tiancai Yin, Shuai Zhao, Cong Gao, Mingbo Yang, Tiehu Li and Bin Jiang

Materials 2026, 19(3), 593; https://doi.org/10.3390/ma19030593 - 3 Feb 2026

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Abstract

Fe-rich phases are unavoidable intermetallic compounds in aluminum alloys, particularly in recycled aluminum. Their needle-like morphology not only impairs the mechanical performance of the alloy by disrupting the continuity of the matrix but also significantly reduces the allowable addition of recycled aluminum materials. [...] Read more.

Fe-rich phases are unavoidable intermetallic compounds in aluminum alloys, particularly in recycled aluminum. Their needle-like morphology not only impairs the mechanical performance of the alloy by disrupting the continuity of the matrix but also significantly reduces the allowable addition of recycled aluminum materials. Based on this, this study focuses on the Al-7Si-0.35Mg-0.35Fe alloy with a high Fe content. The Cr was introduced to modify the characteristics of the Fe-rich phase, and the microstructural evolution and mechanical properties of the aluminum alloy with different Cr content (0–0.25 wt.%) were investigated. Experimental results show that the secondary dendrite arm spacing of the alloy is significantly refined after Cr addition. Meanwhile, the Fe-rich phase gradually transitions from β-Al₅FeSi with needle-like morphology to α-Al₁₅(Fe,Cr)₃Si₂ with short rod-like or blocky morphology as the Cr content increases. Notably, the Fe-rich phase in the 0.20Cr alloy exhibits an approximately 65% increase in sphericity and an 84% reduction in equivalent diameter compared to those in the 0Cr alloy. The morphological blunting and dispersed distribution of Fe-rich phases lead to a broad effective Cr addition range of 0.05–0.20 wt% in the alloy. Among them, the 0.20Cr alloy exhibited the best comprehensive mechanical properties, with its ultimate tensile strength and elongation approximately 19% and 107% higher than those of the 0Cr alloy, respectively. Furthermore, the fracture morphology and the relationship between the Fe-rich phase and microcracks in Al-7Si-0.35Mg-0.35Fe alloys with different Cr contents were also analyzed. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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12 pages, 7074 KB

Open AccessArticle

Mechanical Properties and Fracture Behavior of Hot Isostatically Pressed TiC/TC4 Composites

by Zhiyu Sun, Jinyi Duan, Xiang Wu, Xiaofei Mo, Hai Nan, Jingchao Xu, Ao Fu, Yuankui Cao and Bin Liu

Materials 2025, 18(24), 5529; https://doi.org/10.3390/ma18245529 - 9 Dec 2025

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Abstract

Titanium matrix composites (TMCs), characterized by low density, high strength, and excellent high-temperature mechanical properties, are becoming preferred materials for key components in aerospace engines. However, conventional casting methods for preparing TMCs often encounter issues such as composition segregation and coarse reinforcement phases, [...] Read more.

Titanium matrix composites (TMCs), characterized by low density, high strength, and excellent high-temperature mechanical properties, are becoming preferred materials for key components in aerospace engines. However, conventional casting methods for preparing TMCs often encounter issues such as composition segregation and coarse reinforcement phases, hindering their engineering application. In this study, we fabricated TiC/TC4 titanium matrix composites via hot isostatic pressing (HIP). The composites exhibited room-temperature tensile strength of 1058 ± 8 MPa, yield strength of 958 ± 12 MPa, and total elongation of 17.0 ± 0.5%. Furthermore, the TiC/TC4 composites demonstrated favorable high-temperature mechanical properties, with a tensile strength of about 500 MPa at 600 °C. Investigation into plastic deformation and fracture behavior revealed that at room temperature, tensile cracks initiated predominantly around the reinforcing TiC particles, whereas at high temperatures, cracks primarily originated within the matrix. The strengthening mechanisms of the TiC particle-reinforced TC4 composites included particle strengthening, solid solution strengthening, and load-transfer strengthening. Additionally, the precipitation of nano-acicular secondary α (αs) phases within the β phase during high-temperature tensile deformation was observed, contributing to the superior high-temperature mechanical performance of the composites. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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19 pages, 25806 KB

Open AccessArticle

Optimizing the Y Content of Welding Wire for TIG Welding of Sand-Cast Mg-Y-RE-Zr Alloy

by Yikai Gong, Guangling Wei, Xin Tong, Guonan Liu, Yingxin Wang and Wenjiang Ding

Materials 2025, 18(19), 4549; https://doi.org/10.3390/ma18194549 - 30 Sep 2025

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Abstract

The widespread application of WE43 (Mg-4Y-2Nd-1Gd-0.5Zr) alloy castings in aerospace components is hindered by the frequent formation of defects such as cracks, pores, and especially yttria inclusions. These defects necessitate subsequent welding. However, using homologous WE43 filler wires often exacerbates these issues, leading [...] Read more.

The widespread application of WE43 (Mg-4Y-2Nd-1Gd-0.5Zr) alloy castings in aerospace components is hindered by the frequent formation of defects such as cracks, pores, and especially yttria inclusions. These defects necessitate subsequent welding. However, using homologous WE43 filler wires often exacerbates these issues, leading to high crack susceptibility and reintroduction of inclusions. Herein, we propose a novel strategy of tailoring Y content in filler wires to achieve high-quality welded joint of WE43 sand castings. Systematic investigations reveal that reducing Y content to 2 wt.% (WE23) effectively suppresses oxide inclusion formation and significantly enhances the integrity of the joint. The fusion zone microstructure evolves distinctly with varying Y levels: grain size initially increases, peaking at 24 μm with WE43 wire, then decreases with further Y addition. Moreover, eutectic compounds transition from a semi-continuous to a continuous network structure with increasing Y content, deteriorating mechanical performance. Notably, joints welded with WE23 filler exhibit minimal performance loss, with ultimate tensile strength, yield strength, and elongation reaching 93.0%, 98.0%, and 97.4% of the sand-cast base metal, respectively. The underlying strengthening mechanisms and solute-second phase relationships are elucidated, highlighting the efficacy of optimizing Y content in welding wire design. This study provides valuable insights toward defect-free welding of high-performance Mg-RE alloy castings. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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15 pages, 4684 KB

Open AccessArticle

Corrosion-Wear Mechanism of (AlTiV)_100−xCr_x Lightweight High-Entropy Alloy in the 3.5 wt.% NaCl Solution

by Jiakai Huang, Peng Zhang, Junjie Yang, Wei Li, Qiwei Wang and Jie Li

Materials 2025, 18(11), 2670; https://doi.org/10.3390/ma18112670 - 5 Jun 2025

Cited by 1 | Viewed by 1136

Abstract

(AlTiV)_100−xCr_x high-entropy alloys (HEAs) is expected to solve the problem of poor corrosion-wear resistance of lightweight alloys. To elucidate its corrosion-wear mechanism, three (AlTiV)_100−xCr_x alloys were prepared by vacuum arc melting method by repeating the melting five [...] Read more.

(AlTiV)_100−xCr_x high-entropy alloys (HEAs) is expected to solve the problem of poor corrosion-wear resistance of lightweight alloys. To elucidate its corrosion-wear mechanism, three (AlTiV)_100−xCr_x alloys were prepared by vacuum arc melting method by repeating the melting five times at 240 A current.and their microstructures, mechanics, corrosion, wear, and corrosion-wear behaviors were investigated. The results indicate that (AlTiV)_100−xCr_x is a single-phase with BCC structure and the VEC of Cr5, Cr10 and Cr15 were 4.0, 4.1 and 4.2 respectively. Their hardness increase and toughness and corrosion resistance decrease with the increase of Cr content (Cr5:537.5 HV_0.2/6.7%/1.86 × 10⁻⁸ A/cm²; Cr10:572.3 HV_0.2/5.6%/2.09 × 10⁸ A/cm²; Cr15:617.6 HV_0.2/3.8%/2.51 × 10⁻⁸ A/cm²). The wear volume and the corrosion-wear volume of AlTiVCr alloys are mainly caused by the abrasive wear. However, the fatigue wear of AlTiVCr alloys could be exacerbated by a decrease in material’s toughness, corrosion resistance, and an increase in solution corrosivity. Therefore, Cr10 presents the optimal wear resistance in the deionized water, while the optimal corrosion-wear resistance in the 3.5 wt.% NaCl solution is presented by Cr5. Compared to TC4, the wear and corrosion-wear resistance were improved by 56.4% and 65.5%, respectively. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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Review

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23 pages, 25064 KB

Open AccessReview

Welding of Advanced Aluminum–Lithium Alloys: Weldability, Processing Technologies, and Grain Structure Control

by Qi Li, Qiman Wang, Yangyang Xu, Peng Sun, Kefan Wang, Xin Tong, Guohua Wu, Liang Zhang, Yong Xu and Wenjiang Ding

Materials 2026, 19(4), 738; https://doi.org/10.3390/ma19040738 - 14 Feb 2026

Viewed by 466

Abstract

Aluminum–lithium (Al-Li) alloys are extensively employed in aerospace and space structures because of their low density, high specific stiffness, and excellent fatigue resistance. However, welding of these alloys remains challenging, since the joints typically exhibit unique microstructural features, including equiaxed grain zones (EQZ) [...] Read more.

Aluminum–lithium (Al-Li) alloys are extensively employed in aerospace and space structures because of their low density, high specific stiffness, and excellent fatigue resistance. However, welding of these alloys remains challenging, since the joints typically exhibit unique microstructural features, including equiaxed grain zones (EQZ) along the fusion boundary and coarse columnar grains in the fusion zone, which degrade mechanical performance and increase susceptibility to cracking. This review provides an overview of the generational evolution of Al-Li alloys and their associated weldability, highlights the advantages and limitations of major welding processes, such as laser, arc, and hybrid techniques, and systematically examines the formation mechanisms of EQZ, columnar grains, and equiaxed grain bands. Various strategies for microstructural control are compared, including filler design, pulsed current, and external-field-assisted welding. Special attention is given to grain refinement achieved through heterogeneous nucleation, dendrite fragmentation, and columnar-to-equiaxed transition. Finally, prospects for advanced microstructural control strategies are discussed, with the goal of achieving high-quality welds for next-generation lightweight structural applications. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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19 pages, 3956 KB

Open AccessReview

Recent Advances in κ-Carbide Precipitation Behavior and Its Influence on Mechanical Properties in Austenite-Based Fe-Mn-Al-C Lightweight Steels

by Yanjie Mou, Kai Lei, Jiahao Li, Xiaofei Guo, Jianwen Fan, Chundong Hu and Han Dong

Materials 2026, 19(4), 727; https://doi.org/10.3390/ma19040727 - 13 Feb 2026

Viewed by 563

Abstract

Austenitic Fe-Mn-Al-C lightweight steels have attracted considerable interest for automotive applications due to their exceptional specific strength, where κ-carbides precipitation critically influences mechanical properties. This review systematically examines the crystal structure, classification, and precipitation kinetics of κ-carbides, emphasizing their spatial distribution-dependent effects: coarse [...] Read more.

Austenitic Fe-Mn-Al-C lightweight steels have attracted considerable interest for automotive applications due to their exceptional specific strength, where κ-carbides precipitation critically influences mechanical properties. This review systematically examines the crystal structure, classification, and precipitation kinetics of κ-carbides, emphasizing their spatial distribution-dependent effects: coarse κ-carbides at austenite grain boundaries induce embrittlement and degrade toughness, while nanoscale κ’-carbides within grains enhance strength and ductility through dislocation interactions (e.g., Orowan bypassing and shearing), activating deformation mechanisms such as Dynamic Slip Band Refinement (DSBR), Shear Band-Induced Plasticity (SIP), and Microband-Induced Plasticity (MBIP). Thermodynamic calculations guide alloy design to ensure a single-phase austenite structure at the typical hot-rolling finishing temperature (~900 °C), avoiding harmful phases while promoting beneficial precipitates. Mn suppresses κ-carbide formation, whereas Al and C act as promoters, with intragranular κ’-carbides favoring higher Al/C concentrations (e.g., >6.2% Al and >1.0% C). Heat treatment parameters critically influence κ-carbide distribution, where rapid cooling (e.g., water quenching) suppresses κ-carbides, and subsequent aging (500–700 °C) enables homogeneous precipitation of κ’-carbides. Pre-deformation prior to annealing further accelerates κ-carbide nucleation by introducing crystal defects. Optimal performance requires integrated composition-processing-microstructure optimization to achieve a nnanoscaleκ’-carbide-strengthened austenite matrix through controlled composition and thermo-mechanical processing to achieve an optimal strength-ductility balance. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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23 pages, 7092 KB

Open AccessReview

Toward High-Performance Mg-Matrix Composites: Recent Advances in Ceramic Reinforcement Strategies and Processing Innovations

by Yuefeng Ying, Weideng Wang, Guoqiang You, Yan Yang, Bin Jiang, Lin Yue and Qilin Shao

Materials 2026, 19(2), 365; https://doi.org/10.3390/ma19020365 - 16 Jan 2026

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Abstract

Magnesium matrix composites formed by incorporating ceramic particles into a magnesium alloy matrix can effectively leverage the complementary properties of the matrix and reinforcement. This approach significantly enhances the mechanical properties of the material at both room and elevated temperatures, offering a viable [...] Read more.

Magnesium matrix composites formed by incorporating ceramic particles into a magnesium alloy matrix can effectively leverage the complementary properties of the matrix and reinforcement. This approach significantly enhances the mechanical properties of the material at both room and elevated temperatures, offering a viable solution to the inherent limitations of Mg alloys, such as insufficient absolute strength, stiffness, and poor heat resistance. This article reviews the latest research progress in the field of ceramic particle-reinforced magnesium matrix composites in recent years. First, the current research status of magnesium matrix composites reinforced with different types of ceramic particles is comprehensively summarized. Subsequently, it provides a summary and in-depth analysis of the principles, key technologies, and microstructural characteristics of both mainstream and emerging preparation processes, and discusses their advantages and disadvantages. Finally, the challenges in current research are analyzed, and future cutting-edge directions for developing high-performance ceramic particle-reinforced magnesium matrix composites are discussed. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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44 pages, 21090 KB

Open AccessReview

Review of Molecular Dynamics Simulation of Bimetallic Interfacial Behavior

by Xiaoqiong Wang, Yuejia Wang, Guangyu Li, Wenming Jiang, Jun Wang, Xing Kang, Qiantong Zeng, Shan Yao and Pingkun Yao

Materials 2025, 18(13), 3048; https://doi.org/10.3390/ma18133048 - 26 Jun 2025

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Abstract

Bimetals have broad application prospects in many fields due to the combination of the performance characteristics of the two materials, but weak interface bonding limits their promotion and application. Therefore, studying the interfacial behavior to achieve bimetallic strengthening is the focus of this [...] Read more.

Bimetals have broad application prospects in many fields due to the combination of the performance characteristics of the two materials, but weak interface bonding limits their promotion and application. Therefore, studying the interfacial behavior to achieve bimetallic strengthening is the focus of this field. However, it is often difficult or costly to visually observe the interfacial behavior using traditional experimental methods. Molecular dynamics (MD) is an advanced microscopic simulation method that can conveniently, rapidly, accurately and intuitively study the diffusion and mechanical behavior at the bimetallic interfaces, providing a powerful tool and theoretical guidance to reveal the nature of interfacial bonding and the strengthening mechanism. This paper summarizes the research progress on molecular dynamics in the bimetallic formation process and mechanical behavior, including Al/Cu, Al/Mg, Al/Ni, Al/Ti, Al/Fe, Cu/Ni, and Fe/Cu. In addition, the future development direction is outlined to provide theoretical basis and experimental guidance for further exploring the formation process and performance enhancement of the bimetallic interfaces. Full article

(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)

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