A multiscale-phase-structured CrFeNiW0.1 medium entropy alloy with outstanding strength-ductility synergy

CrFeNi medium entropy alloy (MEA) with single-phase face-centered cubic structure (FCC) can exhibit outstanding ductility but with lower yield strength, which limited its application in engineering filed. To address this issue, the W element, which has a larger atomic size, was selected to be added into CrFeNi MEA. After thermal-mechanical processing, a CrFeNiW 0.1 MEA with a multiscale phase structure can be obtained, and its microstructure, mechanical properties and precipitation behavior were then systematically investigated. σ phase particles with average grain sizes of ∼900 nm and ∼4.7 μm as well as μ phase nanoparticles were found in cold-rolled CrFeNiW 0.1 MEA after heat treatment at 900 °C for 1 h. The yield strength (YS) and ultimate tensile strength (UTS) of CrFeNiW 0.1 alloy with a multiscale phase structure can reach ∼767 MPa and ∼1023 MPa, respectively, while maintaining good ductility of ∼10.6 %. Grain refinement strengthening and precipitation strengthening primarily resulted in the enhancement of yield strength in CrFeNiW 0.1 MEA.