Investigation of phase stability, mechanical properties, and tribological behavior of Al-based entropy alloys

This study investigates three novel Al-based entropy alloys in the Al_90-xCu₅Zn₅(Mg,Sn,Ti)_X system. The empirical thermo-physical parameters and CALPHAD calculations were studied to comprehend phase stability. Although empirical parameters suggested potential for solid solution formation, CALPHAD calculations predicted multiphase microstructures, which were confirmed through experimental analyses. Microstructural characterization and cooling curve analyses revealed the formation of various phases at specific temperatures during solidification. The addition of Mg increased hardness through Mg₂Sn phase formation, while Ti further enhanced hardness by stabilizing primary Al₃Ti phase. Mechanical testing demonstrated a strength-ductility trade-off, with Ti-containing alloy exhibiting the highest compressive strength but lowest ductility. Wear resistance of the experimental alloys was higher than AlSi10MnMg, and Mg and Ti additions improved wear performance compared to AlSi9Cu3(Fe). This comprehensive study highlights the potential of Al–Cu–Zn based multi principal component alloys with Mg, Sn, and Ti additions for developing lightweight materials with tailored mechanical and tribological properties.