EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The present study attempted to understand the development of microstructure and texture in FCC equiatomic CoCrFeMnNi high entropy alloy during severe warm-rolling and compare the results vis-à-vis cold-rolling. The HEA was processed by warm-rolling up to 90% reduction in thickness at 600°C and at temperatures ranging from 700 °C to 1200 °C. The severely warm-rolled HEA showed a lamellar yet coarser microstructure compared to the 90% cold-rolled HEA owing to the dynamic annihilation of dislocations during deformation. Warm-rolled HEA showed a pure metal or copper type deformation texture while the cold-rolled HEA was featured by brass or alloy type texture. The transition in the deformation texture could be appreciated by the increase in the SFE at the elevated deformation temperature, which was conducive for homogeneous deformation by dislocation slip. Warm-rolled materials showed higher recrystallization temperature and coarser recrystallized grain size due to the lower stored energy and coarser deformation microstructure. Annealing resulted in the weakening of the recrystallization texture in both warm- and cold-rolled HEA. The recrystallization texture in both warm- and cold-rolled HEA indicated the absence of strong preferential nucleation or growth upon annealing. The warm-rolled HEA showed an attractive combination of strength and ductility upon annealing at 750°C indicating that warm-rolling could be an effective and interesting processing route for HEAs.