Hot deformation behavior and dynamic recrystallization mechanism of Ti2ZrTa0.75 refractory complex concentrated alloy

Abstract

Hot-deformation behavior and dynamic recrystallization (DRX) mechanism of Ti2ZrTa0.75 refractory complex concentrated alloy were systematically studied via uniaxial compression tests at various deformation temperatures from 800 °C to 1100 °C and different strain rates from 10−3 s−1 to 1 s−1. Stress-strain curves showed an increase in flow stress with decreasing deformation temperature and/or increasing strain rate, and there was continuous strain softening after the peak stress. Microstructure analysis based on electron backscattering diffraction (EBSD) indicated that deformation bands occurred in the hot deformation microstructure with a strain rate of 1 s−1, which is the appropriate location for DRX. Microstructure analysis revealed that DRX occurred during the hot deformation process and DRX fraction and grain size increase with increasing deformation temperature and/or decreasing strain rate. The grain boundary bulging nucleation mechanism and necklace-like structure of DRX grains demonstrate a typical discontinuous dynamic recrystallization (DDRX) process. Cumulative misorientation analysis of the initial grain interior and new grains formed without relying on the initial grain boundaries proved the occurrence of continuous dynamic recrystallization (CDRX).