Work hardening behavior and tensile properties of a high-Mn damping steel at elevated temperatures

An austenite/epsilon-martensite dual-phase high-Mn damping steel was tensile deformed at elevated temperatures to conduct a comprehensive study about the effects of transformation-induced plasticity (TRIP), twinning-induced plasticity (TWIP), dynamic strain aging (DSA) and dislocation slip (DS) on its work hardening behavior and tensile properties. The results showed that the work hardening behavior of high-Mn damping steel can be divided into two stages. In stage-I, the main factor influencing the work hardening changed from gamma -> epsilon transformation to DS as the deformation temperature was increased. In the second stage, the work hardening exponent and ultimate tensile strength were large when intense DSA occurred at 80 degrees C and 120 degrees C, although epsilon -> alpha' transformation became more difficult at elevated temperatures. Tensile deformation at 200 degrees C promoted epsilon -> gamma transformation, such that the work hardening exponent and ultimate elongation were significantly decreased. In the later stage of deformation at 260 degrees C, TWIP effect effectively enhanced the work hardening as deformation induced epsilon -> alpha' transformation occurred at low deformation temperatures.