On the influence of grain size on the TWIP/TRIP-effect and texture development in high-manganese steels

The impact of grain size on the work-hardening rate of two high-manganese steels with nearly identical stacking fault energy values of approximately 16.6 mJ m−2 (X60Mn17 alloy) and 16.5 mJ m−2 (X30MnAl17-1 alloy) was analyzed via macro-texture and micro-texture measurements as well as quasistatic tensile tests and phase analysis. Both alloys exhibited differences in twin volume fraction and volume fraction of the martensitic phase. The twin volume fraction increased with grain size. The X30MnAl17-1 alloy with Al and lower C content showed a lower overall twin volume fraction than the X60Mn17 alloy without Al. Additionally, the phase fractions of e-martensite and α′-martensite were very low in the X30MnAl17-1 alloy. The increased grain size and the subsequent increase in twin volume fraction led to a relative decrease of the volume fraction of grains with -orientation parallel to the tensile axis for both alloys.