Deformation-induced martensite transformation and variant selection in AISI 316L austenitic stainless steel during uniaxial tensile deformation

Present work has investigated the orientation dependence of deformation-induced martensite (DIM) transformation and contemporaneous variant selection in AISI 316L austenitic stainless steel during uniaxial tensile loading. The combined effect of slip and deformation-induced martensite transformation have been analysed comprehensively using experimental macrotexture analysis, visco-plastic self-consistent (VPSC) simulation and reconstruction of prior-austenite orientations from electron backscatter diffraction (EBSD) data. It has been shown that when the polycrystalline austenitic material is deformed, grains with orientations like Brass, Rot-Goss, Rot-Cu undergo plastic deformation by slip and rotate towards {110}<111> orientation. Grains of this orientation eventually undergo DIM transformation at sufficiently higher engineering strain (≥69%) levels. Variant selection during DIM transformation from {110}<111> component of austenite has been critically examined using a model developed based on the phenomenological theory of martensite crystallography (PTMC). It has been observed that in general, variants with higher interaction energies are preferred over the others. The results in turn indicate that Patel-Cohen theory, which is believed to be valid for stress-induced martensite (i.e. during elastic deformation), holds equally good for strain-induced martensite (i.e. during plastic deformation) as well.