Microstructure and deformation mechanism of dual-phase Al 0.5 CoCrNiFe high-entropy alloy

Dual-phase high-entropy alloys containing face-centered cubic (fcc) and body-centered cubic (bcc) phases achieve a combination of high strength and high ductility, which attract extensive attention. Compared with single-phase high-entropy alloys, the dual-phase structure generates more complex deformation mechanisms such as structural transformation and interactions between grain boundaries and dislocations during deformation. In order to understand the structural transformation of the dual-phase high-entropy alloy during deformation and its effect on mechanical properties, Al 0.5 CoCrNiFe high-entropy alloy was prepared and its deformation mechanism was investigated by molecular dynamics simulations combined with experiments. The results show that phase transformation occurred during deformation, and dislocation slip was the main deformation mechanism. In addition, there was significant dislocation pile-up at the interface between fcc and bcc phases after tensile deformation. Temperatures and strain rates significantly affected the mechanical properties and deformation behavior of high-entropy alloys. At low temperature and high strain rate, the dislocation density of the alloy increases after stretching, resulting in the enhancement of tensile strength. Graphical abstract