Effect of Cold Deformation and Heat Treatment on the Microstructure and Mechanical Behavior of High Entropy Alloy CuCrFeNi₂Al_0.5

CuCrFeNi₂Al_0.5, a high entropy alloy (HEA) with a single FCC phase, was deformed at room temperature and then heat treated. The small particles precipitated from the deformed FCC solid solution matrix after heating at 700 °C, softening the solid solution matrix. This outcome confirms that the microstructure of HEAs can be controlled by heat treatment in addition to controlling the chemical composition and the rate of cooling from liquid alloys. The hardness of the samples increased due to precipitation hardening, and the specimen heated at 700 °C with 10% predeformation had the highest hardness. As the predeformation increases, the precipitates tend to interweave in the network morphology. Meanwhile, grains in all specimens became more severely coarse after heat treatment at 1100 °C. Predeformation followed by annealing can obviously slow down the creep rate, indicating that annealing at an appropriate temperature can improve the mechanical properties of deformed HEA.