The Change of Orientation Relationships Between Austenite and α′-Martensite During Deformation in High Manganese TRIP Steel

In situ observation of electron backscattering diffraction technique was used to evaluate the orientation relationships between austenite and α′-martensite (α′-M) for high manganese transformation-induced plasticity steel. It was noted that different from the thermal martensite, which well obeyed K–S relationship with austenite, the orientation relationship between deformation-induced α′-M with austenite changed during deformation, namely K–S and N–W relations coexisted. No clear differences existed between α′-M variants with two kinds of relationships in terms of martensitic orientation, shape and the misorientation between α′-M variants. And this phenomenon happened in almost all austenitic grains with different orientations investigated in this study. An atom displacement mechanism through conjugate complex slips of partial dislocations in the distorted fcc lattice was applied in this article to interpret the coexistence of K–S and N–W relationships.