Phase separation promotes FCC-phase mechanical twinning in AlCoCrFeMo0.05Ni2 high entropy alloy

The AlCoCrFeMo0.05Ni2 high entropy alloy (HEA) can remarkably enhance its ductility through high-temperature annealing. Nevertheless, the underlying mechanism remains under explored. Herein, we utilized molecular dynamics simulations (MD) to calculate the generalized stacking fault energy (GSFE) curves and uniaxial tensile behavior. Notably, the twin inclination of the FCC phase increases significantly after annealing. During plastic deformation, the FCC phase in the annealed alloy exhibits a substantially higher formation of twinning and stacking faults compared to the as-cast alloy. This increased twin inclination after annealing is the fundamental mechanism contributing to the enhancement of high-temperature ductility.