Exploring grain size influence on tensile behavior of 316 H austenitic stainless steel at high temperature: A phenomenological dislocation model

The high temperature mechanical behavior of 316 H austenitic stainless steel with different grain size was investigated in this study through the use of a novel phenomenological dislocation model finite element method. The study was conducted by producing steel specimens with varying grain sizes through adjustments in annealing temperature and time, followed by high temperature tensile tests at 550°C. The finite element method, when integrated with a phenomenological dislocation model that considers grain size parameters, effectively captured the mechanical response under different grain size conditions. Additionally, the two-variable Kocks-Mecking(KM) model accurately captured the grain size effect in 316 H austenitic steel and effectively depicted its tensile flow behavior. The model’s predictions were based on the evolution of forest dislocation density and mobile dislocation density, proving to be a reliable tool for analyzing the microstructural evolution of 316 H austenitic steel specimens with varying grain sizes. This study provides insight into the effect of grain size on the high temperature strength of austenitic stainless steels and demonstrates the utility of a novel phenomenological model finite element method for predicting the mechanical behavior of polycrystalline materials.