Temperature-Dependent Deformation Behavior of 316 Stainless Steel with Heterogeneous Microstructure

Systematic investigations are conducted to elucidate the temperature-dependent mechanical properties and deformation behavior of a heterogeneous structured 316 stainless steel, which features a combination of deformed and reversed/recrystallized grains. It is found that the yield strength of the heterogeneous structured specimen is significantly higher at cryogenic temperature compared to room temperature, whereas the yield strength of the uniformly structured specimen remains largely unchanged. This difference is primarily attributed to the strengthening contribution from dislocations and heterogeneous deformation-induced strengthening in the heterogeneous structured specimen. Additionally, the heterogeneous structured specimen exhibits an impressive elongation of 65.45%, markedly higher than that observed at room temperature. At room temperature, deformation is predominantly driven by dislocation activity. In contrast, under cryogenic condition, the initial stage of deformation is characterized by the plateau due to the transformation-induced plasticity (TRIP) effect. This is followed by the development of localized shear bands, which induce further TRIP effect. These findings suggest that heterogeneous structured 316 stainless steel is well-suited for applications requiring both high strength and toughness in low-temperature environment.