Deformation behaviors of a Fe-20Mn-3Al-3Si TRIP steel under quasi-static compression and dynamic impact

Strain induced phase transformation is one of the fundamental strengthening methods for transformationinduced plasticity (TRIP) steels with low stacking fault energy. In this study, the deformation products of a Fe-20Mn-3Al-3Si TRIP steel after quasi-static compression and dynamic impact were investigated comparatively, to elucidate the effect of strain rate on the deformation mechanisms of this steel. Compared to quasi-static compressive deformation, the strain induced martensitic transformation including the formation of e-martensite and alpha'-martensite is significantly inhibited under the dynamic loading, and the dynamic recovery of dislocation is promoted as well. Moreover, large quantities of strain induced e-martensite twins including {1011} and {1012} e-twins are formed at the intersections of two e-martensite laths instead of the formation of alpha'-martensite in the dynamic impact sample. Due to the transformation of deformation mechanism and lower dislocation density increment, the impact deformation sample shows a lower strain hardening ability during the process of plastic deformation compared with the quasi-static compression sample. Our findings clarify the deformation behavior of the Fe-Mn-Al-Si TRIP steel subjected by dynamic deformation and enrich the theories of strain induced phase transformation.

Automated summary

This study investigates the deformation products of Fe-20Mn-3Al-3Si TRIP steel under quasi-static compression and dynamic impact, focusing on the effect of strain rate on the deformation mechanisms. The results show that the strain induced martensitic transformation is significantly inhibited under dynamic loading, while the dynamic recovery of dislocation is promoted. Additionally, large quantities of strain induced e-martensite twins are formed in the dynamic impact sample. Compared to quasi-static compression, the impact deformation sample exhibits lower strain hardening ability.