Analysis of the γ–ɛ–α′ variant selection induced by 10% plastic deformation in 304 stainless steel at −60 °C

The texture changes occurring by phase transformations, induced by 10% plastic deformation of a 304 stainless steel sheet at T = −60 °C have been analysed. The inherited α′ texture is obtained from the austenitic γ texture with variant selection involving the intermediate HCP ɛ phase. The local orientation analysis of the different phases suggested that the applied stress first promotes the ɛ variants in a γ grain. At this stage, a strong variant selection often occurs due to the influence of the external applied stress. Then, the selected ɛ variants transform into α′ variants. The selection of these consecutive α′ variants is more complex because of the superposition of the applied stress and the internal stresses due to the formation of the ɛ variants themselves. We analysed these transformations in austenitic grains at the light of the γ–ɛ and ɛ–α′ transformation mechanisms. The selected variants, calculated according to these mechanisms are in fair agreement with the experimental ones.