Evolution of microstructure and hardness in a dual‐phase Al 0.5 CoCrFeNi high‐entropy alloy with different grain sizes

Cold‐rolling with subsequent annealing was carried out to produce recrystallized structures with different grain sizes in an Al 0.5 CoCrFeNi high‐entropy alloy to systematically investigate the grain growth behavior and varying properties. The results show that recrystallized microstructures can be achieved through an annealing process at 1200 °C for 75 min to 16 h, and the average grain size in this study ranges from 5.33 to 30.03 µm. The hardness shown to be affected through grain coarsening was then measured as a function of the grain size, and it is found to follow the classical Hall–Petch strengthening.