Comprehensive Analysis of Hot Deformation Characteristics in High-Mn Steel: Sensitivity to Temperature and Strain Rate
摘要
The hot deformation and dynamic recrystallization (DRX) behaviour of high-Mn steel were investigated by performing hot compression experiments over a strain rate range of 0.01 to 10 s−1 and a temperature range of 1073 K to 1373 K. The processing map developed for the steel exhibits an instability region at temperatures below 1173 K and a strain rate exceeding 1 s−1. In contrast, the remaining strain rate-temperature space corresponds to a stable domain, with a peak efficiency of ~ 31 pct observed at 1373 K over the strain rate range of 0.01 to 10 s−1. Electron backscatter diffraction analysis revealed that the DRX fraction is higher at both low (0.01 s−1) and high (10 s−1) strain rates in comparison to intermediate strain rates (~ 0.1 to 1 s−1). Additionally, the transition from discontinuous DRX (DDRX) to continuous DRX (CDRX) mechanism is observed with an increase in temperature from 1073 K at 0.01 s−1 or a decrease in strain rate from 10 to 1 s−1 at 1373 K. The transition in the DRX mechanism with variation in temperature and strain rate is associated with stacking fault energy (SFE) and stored energy, respectively. Furthermore, the Kocks and Mecking (KM) model was employed to estimate the recovery rate and DRX kinetics. The recovery rate parameter decreases with an increase in strain rate and increases with an increase in temperature and temperature-dependent SFE. Furthermore, the incorporation of DRX into the KM model demonstrates that DRX kinetics increase as the strain rate increases at 1373 K.