Influence of strain rate, temperature, and strain-induced martensite on residual stress evolution during tensile deformation of SS 304L

The deformation of polycrystalline materials and associated phase transformation causes elastic residual stress (RS) to remain within the material under equilibrium conditions. The present study focused on the influence of strain rate and strain-induced martensitic (SIM) transformation on the RS evolution in stainless steel (SS) of grade 304L during deformation at room temperature (RT) and 200 degrees C. The RS distribution in tensile deformed specimens was analysed using X-ray diffraction, while microstructural characterisation was performed with electron back-scatter diffraction. The study examines the RS and residual shear stress in the austenite and martensite phases, emphasising on the variations in RS with strain rate and temperature. The analysis of RS in the gauge region indicates that strain rate significantly affects the RS in the dual-phase alloy, with SIM transformation reducing RS in the austenite phase. Further, variations in RS are discussed in correlation with the changes in SIM volume fraction, mechanical properties, and tensile behaviour of the SS 304L. Additionally, the study explores the potential of RS and full width at half maxima of the X-ray diffraction peak as indicators for assessing deformation levels.