Mechanical properties and wear behaviors of lightweight Al3Ti-based medium-entropy alloys at elevated temperatures

Al 3 Ti-based medium-entropy alloys (MEAs) with improved high-temperature mechanical properties and wear resistance were fabricated using arc melting method via alloying Al 3 Ti with various amounts of Cr, Mn, Fe and Cu elements. The alloying elements, Cr, Mn, Fe, and Cu, transformed the brittle D0 22 structure into a ductile L1 2 structure, along with the formation of hard B2 and D8a second phases. The resultant combination of improved ductility and strength enhances the mechanical performance of the material. A representative alloy, Al 60 Ti 20 Cr 5 Mn 5 Fe 5 Cu 5 , achieved high yield strength and high hardness of 442 MPa and 270HV2 at even 500 °C. Wear tests showed that the Al 3 Ti-based MEAs distinctly outperformed conventional Al-matrix composite reinforced with 30 wt% of SiC particles at both room temperature and 300 °C. The ordered L1 2 , B2, and D8a phases not only led to good room-temperature strength and hardness, but also contributed to high thermal stability, contrasting with solid solution alloys, resulting in superior high-temperature performance. The results highlight Al 3 Ti-based MEAs as competitive candidates for medium-temperature applications, bridging the gap between aluminum and titanium alloys in engineering applications. • Lightweight Al 3 Ti-based medium-entropy alloys (MEAs) were designed, fabricated and investigated. • Alloying Al 3 Ti with Cr, Mn, Fe, and Cu transformed D022 Al 3 Ti into L12 matrix with B2 and D8a second phases. • Al 3 Ti-based MEAs can be readily tailored for low density, high strength, and reasonable ductility. • Al 3 Ti-based MEAs showed superior wear resistance to those of Al-30 wt% SiCp composite and Ti6Al4V. • Representative Al 60 Ti 20 Cr 5 Mn 5 Fe 5 Cu 5 is promising for mechanical and tribological applications at medium temperatures.