kinetics of austenite recrystallization during the annealing of cold-rolled fe-mn-al-c steel

In the current study, the recrystallization behavior of 75% cold-rolled fe-22mn-10al-1.4c steel during annealing at 750, 770, 790, 810, and 830°c was studied. x-ray diffraction patterns and optical microscopy were used to characterize microstructures. the vickers micro-hardness test was used to characterize recrystallization kinetics during annealing. johnson-mehl-avrami-kolmogorov (jmak) model was used to evaluate the experimental data. the as-homogenized microstructure illustrated only austenite with a high fraction of annealing twins, and austenite to martensite phase transformation was not observed after quenching at a high temperature and also until high thickness reduction. avrami exponent was decreased from 0.76 to 0.42, with increasing the annealing temperature from 750 to 830°c. the activation energy value was determined to be ~175 kj/mol, which was slightly higher than the diffusion activation energy of carbon in austenite.