Phase composition of 15Mn-0.1C-0.4/1.4Al-Si TRIP/TWIP steels after cold rolling and annealing

In the steel industry, research efforts have been mainly focused on high-strength steels recently. These steels find use in both automotive industry and (thanks to reduced weight of structural parts) aircraft industry. New possibilities emerged at the beginning of this century, when the effect of strain-induced transformation of γ phase was attempted to be applied in austenitic steels. Particularly the high manganese steels are extremely ductile austenitic steels characterized by a high rate of work hardening resulting from the generation of deformation-nucleated twins and possibly combined with the deformation induced formation of martensite. Capability of energy absorption is much bigger in comparison with conventional steels. This paper deals with the description of the phase composition of two heats of steel with 15 wt. % of manganese after annealing after cold rolling with 40% reduction of thickness. Various methods of phase analysis have been used: colour etching, EBSD and X-ray diffraction.