Nano-twinned steel exhibits high mechanical properties obtained through ultra-rapid heat treatment

Ultra-rapid heat treatment was performed on cold rolled high manganese TWIP steel. This process obtains very high mechanical strength and good ductility through the recovery of dislocations, whereas the twins introduced during the cold rolling remain thin and stable. The maximal temperature to retain high yield strength is shown to be around 615°C, where the first recrystallized grains appear. This heat treatment is found to provide reproducible properties across a wide temperature range and could thus open new perspectives for this type of steel. Finally, a physically based model is used to predict the yield strength resulting from ultra-rapid heat treatments.