Dynamic recrystallization of a high-Mn TWIP steel during multiple forging at 800°C

The mechanisms of the microstructure evolution in a high-manganese TWIP steel, Fe–0.03% C–28% Mn– 1.5% Al, during multiple forging at a temperature of 800°C were studied. Multiple forging to a total strain of 4 leads to an increase in the ultimate tensile strength to 580 MPa, the yield strength to 400 MPa with a total elongation of 45%. The flow curve that envelops all compression passes is characterized by a peak of the flow stresses at a total strain of about 0.5, followed by softening and a steady state deformation at a strain above 2, which was frequently observed in the case of discontinuous dynamic recrystallization (DRX). However, the rapid development of strain-induced boundaries near initial boundaries and along the deformation microbands suggests continuous DRX mechanism. Therefore, the structural changes are associated with the occurrence of discontinuous and continuous DRX, leading to rapid grain refinement to 2.5 ± 0.5 µm.