Mechanical properties and microstructural evolution of a novel (FeCoNi)(86.93)Al6.17Ti6.9 medium entropy alloy fabricated via powder metallurgy technique

摘要

Strength-ductility synergy is considered as a long-standing contradiction in high-performance structural materials. Here, we fabricated an equiatomic FeCoNi MEA enhanced by nano-scaled L1(2) precipitates with outstanding mechanical properties via powder metallurgy (PAM) techniques. Compared with the FeCoNi MEA, this precipitation-strengthened FeCoNi MEA exhibits higher yield strength (796 MPa) and ultimate tensile strength (1268 MPa), and maintains moderate ductility of 20.3%. The strength improvement is mainly attributed to the grain refinement and dislocation pinning, caused by densely dispersed L1(2) nanoparticles with a volume fraction of about 48.7 vol%. This work provides a new strategy to design high-performance structural materials. (C) 2020 Published by Elsevier B.V.