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

An austenite/ε-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 γ → ε 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 °C and 120 °C, although ε → α′ transformation became more difficult at elevated temperatures. Tensile deformation at 200 °C promoted ε → γ transformation, such that the work hardening exponent and ultimate elongation were significantly decreased. In the later stage of deformation at 260 °C, TWIP effect effectively enhanced the work hardening as deformation-induced ε → α′ transformation occurred at low deformation temperatures.