Phase transformation at low temperature during low cycle fatigue and its Reversion in SS316L: An experimental and MD simulation study

The present study investigates the phase transformation processes in SS316L during Low Cycle Fatigue (LCF) and reversion heat treatment. The LCF tests were carried out at different strain amplitudes (0.6%, 0.8%, 1%, and 1.2%) at −80°C and 10 −3 s −1 strain rate, which transforms γ-austenite phase to deformation induced martensite (DIM). Subsequently, all the deformed samples were annealed at 700°C for an hour to retransform DIM to the γ-austenite phase. Extensive microstructure analysis was performed using Electron Backscatter Diffraction (EBSD) and X-ray Diffraction (XRD) techniques to understand the phase transformation and reversion processes. Molecular dynamics simulated the DIM formation during LCF, revealing fcc to hcp (ε-martensite) and bcc (α’-martensite) phases in compression but no phase transformation during the tensile cycle.