Heterostructure-enabled creep resistance and deformation mechanisms in a new Ni-Co-based high-entropy alloy

A novel Ni-Co-based high-entropy alloy (HEA) featuring a stable FCC + L12 dual-phase structure was developed to address creep embrittlement at intermediate temperature. By creating heterostructures in the present HEA, the yield strength of Ni-Co-based HEA was significantly improved from 1100 MPa to 1500 MPa with an acceptable tensile elongation of 10%. Simultaneously, the creep embrittlement can be defeated in their heterogeneous counterparts with a superior low steady creep rate of 0.00044%/h at 725 °C and 630 MPa. Transmission electron microscopy evidence suggests that the anti-phase boundaries (APBs) and superlattice intrinsic stacking faults (SISFs) shear the precipitates during the deformation.