Hot deformation behavior and mechanism of cold deformed CoCrCu1.2FeNi high entropy alloy

Abstract

The high temperature deformation behavior and mechanisms of the cold-deformed CoCrCu1.2FeNi high-entropy alloy (HEA) were investigated by optical microscope (OM), scanning electron microscope (SEM) and electron backscattered diffraction (EBSD) at temperatures and strain rates of 950–1100 °C and 0.001–1 s−1, respectively. The results show that the flow stress increases as the deformation temperature decreases and the strain rate increases, and there is significant dynamic recrystallization (DRX) during the deformation process. 1050–1090 °C/0.02–1 s−1 and 975–1050 °C/0.002–0.2 s−1 are the optional hot temperature deformation regions. Discontinuous dynamic recrystallization (DDRX) occurs at different temperatures when the strain rate is 0.001 s−1 with a maximum recrystallization percentage of 90.28 %. The DRX degree gradually increases as the temperature rises from 950 °C to 1000 °C and from 1050 °C to 1100 °C. The maximum polar density of texture sharply increases to 11.78 at 1050 °C. The deformed microstructure leads to an increase in dislocation density, which could be effectively reduced by DRX.