Study on Hydrogen Embrittlement Behavior of 316L Austenitic Stainless Steel Based on Digital Image Correlation

ABSTRACT The effect of hydrogen on the strain hardening or softening behavior of 316L stainless steel during the plastic deformation stage remains controversial. The influence of hydrogen on the plastic deformation and fracture behavior of 316L austenitic stainless steel was investigated using digital image correlation (DIC) and finite element method (FEM) in this study. The results show that hydrogen reduces the fracture strain of the material. After 48 h of hydrogen charging, the hydrogen embrittlement sensitivity index reaches 13.85%, whereas its effect on the hardening or softening behavior of the material can be considered negligible. DIC and FEM analyses indicate that hydrogen promotes strain localization and accelerates the onset of necking, leading to premature fracture before full macroscopic plastic deformation can develop. This further confirms that hydrogen primarily reduces the fracture strain of 316L stainless steel, without significantly influencing its hardening or softening behavior. Scanning electron microscope (SEM) fractography reveals that hydrogen‐induced damage transforms the fracture morphology from large and deep dimples to small and shallow dimples, indicating that the microvoid coalescence process is significantly accelerated, which is consistent with the premature fracture behavior observed by DIC/FEM.