The superior strength-ductility combination of a (Ni2FeCoCr)88.25-Al5Ti3W1.5Mo1.5Nb0.75 high entropy alloy enhanced with the heterogeneous microstructure via thermo-mechanical processing

A Ni-rich NiFeCoCr-based high entropy alloy (HEA) doped with (W, Mo, Al, Ti, Nb) was designed and prepared. After thermo-mechanical processing, the microstructure and tensile property was investigated. Via 80% reduction cold-rolling, 900 °C/20 min annealing and 750 °C/24 h aging, the alloy exhibits a superior combination of strength and ductility. The yield strength can reach up to 1823 MPa with an elongation of 10.2%. The commendable property is attributed to the heterogeneous microstructure that consists of recrystallized and non-recrystallized matrix grains with dislocations, stacking faults, twins, micron (Ti, Nb)-rich phase, sub-micron σ phase and nano/sub-micron γ′ phase. The secondary phase precipitates and dislocations play a dominant role in strengthening the alloy.