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

Highlights: • A novel precipitation strengthened FeCoNi MEA were synthesized through powder metallurgy method. • This Al6Ti7 MEA exhibits a high yield strength (796 MPa) with moderate ductility retention (20.3%). • The high strength is mainly attributed to the highly dispersed L1₂ nanoparticles, leading to precipitation strengthening. -- Abstract: 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 L1₂ precipitates with outstanding mechanical properties via powder metallurgy (P/M) 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 L1₂ nanoparticles with a volume fraction of about 48.7 vol%. This work provides a new strategy to design high-performance structural materials.