High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios
Enhancing damage tolerance and wear resistance in Al–Si-based alloys under thermomechanical stress remains a key challenge in lightweight structural applications. This study investigates the microstructural and tribomechanical behavior of hypoeutectic Al–Si–(Cu)–Mg alloys with varying Cu:Mg ratios (...
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2025-07-01
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| author | Jaehui Bang Yeontae Kim Eunkyung Lee |
| author_facet | Jaehui Bang Yeontae Kim Eunkyung Lee |
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| description | Enhancing damage tolerance and wear resistance in Al–Si-based alloys under thermomechanical stress remains a key challenge in lightweight structural applications. This study investigates the microstructural and tribomechanical behavior of hypoeutectic Al–Si–(Cu)–Mg alloys with varying Cu:Mg ratios (3:1 vs. 1:3) under a T6 heat treatment. Alloys A and B, with identical Si contents but differing Cu and Mg levels, were subjected to multiscale microstructural characterization and mechanical and wear testing at 25 °C, 150 °C, and 250 °C. Alloy A (Cu-rich) exhibited refined α-Al(FeMn)Si phases and homogeneously dissolved Cu in the Al matrix, promoting lattice contraction and dislocation pinning. In contrast, Alloy B (Mg-rich) retained coarse Mg<sub>2</sub>Si and residual β-AlFeSi phases, which induced local stress concentrations and thermal instability. Under tribological testing, Alloy A showed slightly higher friction coefficients (0.38–0.43) but up to 26.4% lower wear rates across all temperatures. At 250 °C, Alloy B exhibited a 25.2% increase in the wear rate, accompanied by surface degradation such as delamination and spalling due to β-AlFeSi fragmentation and matrix softening. These results confirm that the Cu:Mg ratio critically influences the dominant hardening mechanism—the solid solution vs. precipitation—and determines the high-temperature performance. Alloy A maintained up to 14.1% higher tensile strength and 22.3% higher hardness, exhibiting greater shear resistance and interfacial stability. This work provides a compositionally guided framework for designing thermally durable Al–Si-based alloys with improved wear resistance under elevated temperature conditions. |
| format | Article |
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| institution | DOAJ |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-07-01 |
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| spelling | doaj-art-77c9fc6aec804dc6af2a19a6ebcb86562025-08-20T03:13:44ZengMDPI AGApplied Sciences2076-34172025-07-011514804710.3390/app15148047High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg RatiosJaehui Bang0Yeontae Kim1Eunkyung Lee2Interdisciplinary Major of Maritime AI Convergence, Department of Advanced Materials Convergence Engineering, National Korea Maritime and Ocean University, Busan 49112, Republic of Korea3rd R&D Institute-6th Directorate Division, Agency for Defense Development, Daejeon 34186, Republic of KoreaInterdisciplinary Major of Maritime AI Convergence, Department of Advanced Materials Convergence Engineering, National Korea Maritime and Ocean University, Busan 49112, Republic of KoreaEnhancing damage tolerance and wear resistance in Al–Si-based alloys under thermomechanical stress remains a key challenge in lightweight structural applications. This study investigates the microstructural and tribomechanical behavior of hypoeutectic Al–Si–(Cu)–Mg alloys with varying Cu:Mg ratios (3:1 vs. 1:3) under a T6 heat treatment. Alloys A and B, with identical Si contents but differing Cu and Mg levels, were subjected to multiscale microstructural characterization and mechanical and wear testing at 25 °C, 150 °C, and 250 °C. Alloy A (Cu-rich) exhibited refined α-Al(FeMn)Si phases and homogeneously dissolved Cu in the Al matrix, promoting lattice contraction and dislocation pinning. In contrast, Alloy B (Mg-rich) retained coarse Mg<sub>2</sub>Si and residual β-AlFeSi phases, which induced local stress concentrations and thermal instability. Under tribological testing, Alloy A showed slightly higher friction coefficients (0.38–0.43) but up to 26.4% lower wear rates across all temperatures. At 250 °C, Alloy B exhibited a 25.2% increase in the wear rate, accompanied by surface degradation such as delamination and spalling due to β-AlFeSi fragmentation and matrix softening. These results confirm that the Cu:Mg ratio critically influences the dominant hardening mechanism—the solid solution vs. precipitation—and determines the high-temperature performance. Alloy A maintained up to 14.1% higher tensile strength and 22.3% higher hardness, exhibiting greater shear resistance and interfacial stability. This work provides a compositionally guided framework for designing thermally durable Al–Si-based alloys with improved wear resistance under elevated temperature conditions.https://www.mdpi.com/2076-3417/15/14/8047hypoeutectic Al–Si–(Cu)–Mg alloysCu:Mg ratiosolid solutionprecipitation hardeninghigh-temperature tensilehigh-temperature wear |
| spellingShingle | Jaehui Bang Yeontae Kim Eunkyung Lee High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios Applied Sciences hypoeutectic Al–Si–(Cu)–Mg alloys Cu:Mg ratio solid solution precipitation hardening high-temperature tensile high-temperature wear |
| title | High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios |
| title_full | High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios |
| title_fullStr | High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios |
| title_full_unstemmed | High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios |
| title_short | High-Temperature Mechanical and Wear Behavior of Hypoeutectic Al–Si–(Cu)–Mg Alloys with Hardening Mechanisms Dictated by Varying Cu:Mg Ratios |
| title_sort | high temperature mechanical and wear behavior of hypoeutectic al si cu mg alloys with hardening mechanisms dictated by varying cu mg ratios |
| topic | hypoeutectic Al–Si–(Cu)–Mg alloys Cu:Mg ratio solid solution precipitation hardening high-temperature tensile high-temperature wear |
| url | https://www.mdpi.com/2076-3417/15/14/8047 |
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