Nano-precipitates strengthened non-equiatomic medium-entropy alloy with outstanding tensile properties.

In this work, a novel non-equiamotic Ni 46 Cr 23 Co 23 Al 4 Ti 4 medium-entropy alloy (MEA) strengthened by nanoscale coherent γ′ particles with L1 2 superlattice was successfully synthesized, then its microstructure, mechanical properties, strengthening and deformation mechanism were systemically investigated. Our experimental results demonstrated that this precipitation strengthened MEA exhibited outstanding strength-ductility synergy, combination a high yield strength of ~920 MPa, an ultimate tensile strength of ~1320 MPa and an excellent ductility of ~36%. The nanosized γ′ particles bought out effective precipitation strengthening in this non-equiamotic MEA, contributing a majority yield strength enhancement of ~600 MPa. For this γ′-strengthened MEA, the dominant deformation model was the stacking-faults controlled mode rather than the mechanical twin dominated mode in single-phase face-centered-cubic structure Ni 50 Cr 25 Co 25 MEA. Our work provides a further understanding of precipitate strengthening in non-equiamotic high-entropy alloys (HEAs)/MEAs. • Microstructure and mechanical properties of Ni 46 Cr 23 Co 23 Al 4 Ti 4 were investigated. • The aged Ni 46 Cr 23 Co 23 Al 4 Ti 4 showing outstanding strength-ductility synergy. • The strength and deformation mechanisms of aged Ni 46 Cr 23 Co 23 Al 4 Ti 4 were investigated. [ABSTRACT FROM AUTHOR]