Hot Deformation and Subsequent Annealing on the Microstructure and Hardness of an Al_0.3CoCrFeNi High-entropy Alloy

The influence of simple thermomechanical processing such as hot deformation and heat treatment on the microstructure and hardness of an Al_0.3CoCrFeNi high-entropy alloy has been investigated. Results show that the relatively high deformation temperature can induce discontinuous dynamic recrystallization with fine grains initially nucleating at the elongated grain boundaries. The transition from partial recrystallization to fully recrystallization, as well as the precipitation behavior after annealing, has been described in detail. Both bcc precipitation and completely recrystallized grains can be observed after annealing at 1000 °C. Based on detailed microstructure analysis, the decrease in hardness value is shown to be related to both dynamic recrystallization and dynamic recovery which lead to softening.