Effect of deformation temperature on tensile properties in a pre-cooled Fe-Mn-C austenitic steel

We investigated the tensile deformation behavior of a Fe-17Mn-0.3C (wt%) steel containing thermally-induced HCP-martensite that was formed by cooling to 77 K beforehand from various temperatures. In the temperature range where deformation-induced HCP→FCC reverse transformation and deformation twinning occur, the yield strength was enhanced by the pre-existing HCP-martensite, and the brittle cracking associated with the HCP-martensite was suppressed by the deformation-induced HCP→FCC reverse transformation after yielding. Additionally, the work hardening was sustained by deformation twinning. As a result, the yield and flow stresses were enhanced without any loss in elongation at the specific temperatures that were used in this study.