Effect of strain rate on the work-hardening rate in high-Mn steel

Abstract

In order to investigate the effect of strain rate on the work-hardening rate in high-Mn steel, tensile tests are performed at different strain rates of 10⁻¹ s⁻¹, 10⁻² s⁻¹ and 10⁻³ s⁻¹. Results indicate that high strain rate increases the stacking-fault energy due to the temperature effect. The tested steel has a negative strain rate sensitivity and work-hardening rate sensitivity. The deformation-induced transformations of γ →α′ and γ→ both occur. With the increase of strain rate, the transformation induced plasticity effect becomes weaken, the volume fraction of -martensite decreases, the density of deformation band reduces, the deformation band becomes coarse and the distance between adjacent two deformation bands increases, but the diameter and depth of the dimples get larger, and the number of dimples decreases.