  A novel medium manganese steel named Novalloy with composition
Fe-8.3Mn-3.8Al-1.8Si-0.5C-0.06V-0.05Sn was developed and thermomechanically
processed through hot rolling and intercritical annealing. The steel possessed
a yield strength of 1 GPa, tensile strength of 1.13 GPa and ductility of 41\%.
In order to study the effect of cold rolling after intercritical annealing on
subsequent tensile properties, the steel was further cold rolled up to 20\%
reduction. After cold rolling, it was observed that the strain hardening rate
increased continuously with increasing cold rolling reduction but without a
significant drop in ductility during subsequent tensile tests. The
microstructural evolution with cold rolling reduction was analysed to
understand the mechanisms behind this enhanced TRIP effect. It was found that
cold rolling activated additional twinning systems which provided a large
number of potent nucleation sites for strain induced martensite to form during
subsequent tensile tests.
