Presence of ε-martensite as an intermediate phase during the strain-induced transformation of SUS304 stainless steel

We have investigated the formation process of α′-martensite from the γ-phase induced by external strain using in situ synchrotron diffraction experiments, combined with Lorentz transmission electron microscopy (TEM) and high-resolution TEM observations. It is clearly demonstrated that ε-martensite with hexagonal symmetry appears as an intermediate structure during the plastic deformation of SUS304 stainless steel. In addition to stacking faults and dislocations, interfaces between the twin structures presumably play a key role in the formation of ε-martensite.