Study on Hot Deformation Behavior and Dynamic Recrystallization Mechanism of Cu-Ti-Fe Alloy

Hot compression experiments with the deformation temperatures of 750-950 degrees C and the strain rates of 0.01-10 s-1 are carried out on a Gleeble-3500 thermal-mechanical simulator. The flow behavior and dynamic recrystallization (DRX) mechanism of the Cu-Ti-Fe alloy are systematically studied under different hot deformation conditions. According to the curves of flow stress and work hardening rate, the DRX critical condition of the alloy is obtained, and the critical stress value of DRX is small under high-temperature and low-strain rate. After fitting, the logarithmic values of the critical stress and critical strain have a linear relationship with lnZ, which indicates that the alloy is more prone to DRX at high temperatures and low-strain rates. The Arrhenius constitutive model of the alloy is established, the linear correlation coefficient (R2) is 0.984. Combined with the microstructure of Cu-Ti-Fe alloy, the microstructure evolution characteristics and DRX mechanism are elucidated. The dominant mechanism of the alloy under the deformation temperature of 750-950 degrees C is the DRX mechanism. The low-angle grain boundaries (LAGBs) transform into high-angle grain boundaries (HAGBs) and continuous dynamic recrystallization (CDRX) grains form. Abundant dislocations gather near the HAGBs, causing grain boundaries to protrude. High-temperature conditions make the dislocations disappear, forming discontinuous dynamic recrystallization (DDRX) grains. The dominant mechanism of the Cu-Ti-Fe alloy under the deformation temperature of 750-950 degrees C is the dynamic recrystallization (DRX) mechanism. The dislocation density increases, subgrains containing low-angle grain boundaries (LAGBs) are rearranged by dislocations, the LAGBs transform into high-angle grain boundaries (HAGBs) and continuous dynamic recrystallization (CDRX) grains form. Abundant dislocations gather near the HAGBs, causing grain boundaries to protrude. High-temperature conditions make the dislocations disappear, forming discontinuous dynamic recrystallization (DDRX) grains.image (c) 2023 WILEY-VCH GmbH