Effect of Temperature on Stress–Strain Curve in SUS316L Metastable Austenitic Stainless Steel studied by In Situ Neutron Diffraction Experiments

Abstract

In situ neutron diffraction experiments during tensile deformation were conducted to investigate the effect of temperature on the tensile properties of JIS-SUS316L steel from the phase stresses of austenite (γ) and ferrite (α) phases and the kinetics of deformation-induced martensitic transformation (DIMT). The 0.2% proof stress and tensile strength increased with decreasing deformation temperature, and the maximum uniform elongation was reached at 223 K. The temperature of the maximum uniform elongation in metastable austenitic stainless steels is related to the mechanical stability of γ and showed good correlation with the Ni equivalent. The estimated phase stress of γ at a given true strain increased with decreasing temperature; however, the temperature dependence of the twinning-induced plasticity effect of the γ phase was small. The phase stress of α was almost independent of temperature between 138 K and 223 K. The effect of temperature on the mechanical properties of the SUS316L steel was largely affected by the transformation-induced plasticity effect, which was related to the kinetics of DIMT according to in situ neutron diffraction experiments.