The effect of strain induced ferrite transformation on the microstructural evolutions and mechanical properties of a TRIP-assisted steel

The capability of strain-induced ferrite transformation in refining the microstructure of a promising transformation-induced plasticity (TRIP) steel has been studied in the present investigation. This was performed employing the hot compression testing technique to deform the experimental TRIP steel at temperatures below the austenite-to-ferrite transformation temperature (i.e., Ac3). The strain-induced ferrite transformation (DIFT) has been identified as the most effective mechanism contributing to the grain refinement at temperatures (860 and 880°C) just below the corresponding Ac3. The influence of this phenomenon on the mechanical properties of the material during and after deformation has been fully addressed. The results show that the DIFT would lead to a work softening behavior during deformation. However, the grain refinement through DIFT has significantly improved the mechanical properties of the deformed specimens characterized by the shear punch testing method.