Hydrogen-related with the change in mechanical properties and deformation behavior of 316 L austenite stainless steel

The effect of internal hydrogen on the mechanical properties and deformation behavior of 316 L austenitic stainless steel at temperatures ranging from 123 to 298 K was investigated. Hydrogen was preintroduced into the tested specimens via direct exposure to a high-pressure environment at elevated temperatures. While the tensile strengths of the material were not affected by the internal hydrogen, the relative reduction in area (RRA) decreased with a decrease in the tested temperature, reaching a minimum at 223 K, and inversely increasing with a further decrease in temperature. Hydrogen was found to enhance the slip planarity, which reduced the number of α ‘martensite nucleation sites and the driving force for the nucleation of embryos, thereby exhibiting an austenite stabilization effect and consequently mitigating the formation of the strain-induced martensite (SIM), α’. The maximum degradation of tensile ductility occurring at 223 K was attributed to the most significant reduction in the stacking fault energy (SFE) of the hydrogen pre-charged specimen observed at 223 K, which enhanced the degree of dislocation dissociation into partials during the plastic deformation process and evolution.