Deformation induced martensitic transformation in stainless steels

Deformation induced martensitic transformation was investigated in metastable austenitic stainless steel. This steel can present a microstructure of austenite (γ), α′ martensite and non magnetic ε martensite. Uni-axial tensile test was used for loading at different temperatures below room temperature (from −120 to 20 °C). During the deformation the transformation takes place at certain places in an anisotropic way and texture also develops. Quantitative phase analysis was done by X-ray diffraction (XRD) and magnetic methods while the texture was described by X-ray diffraction using a special inverse pole figure. The quantitative phase analysis has shown that the formation of α′ and ε martensite from austenite is the function of deformation rate, and deformation temperature. The transformation of the textured austenite takes place in an anisotropic way and a well defined crystallographic relationship between the parent and α′ martensite phase has been measured.