3D modelling of hydrogen embrittlement in austenitic stainless steel and nickel-based superalloy: Physical metallurgy aspects on hydrogen entrapment

This study explores the intricate relationship between hydrogen and the microstructural elements of austenitic stainless steels and nickel-based superalloys, with particular focus on their propensity for hydrogen embrittlement (HE). Utilizing sophisticated simulation tools within the ANSYS framework, we have developed an in-depth 3D model that intricately portrays the subtle hydrogen diffusion dynamics as they interact with microstructural features, including grain boundaries, dislocations, precipitates, and the lattice framework. This model illuminates the pivotal roles these microstructural interfaces play in the transportation and trapping of hydrogen and their contribution to the vulnerability of these alloys to HE. Our findings reveal that dislocations serve as a critical factor in dictating hydrogen diffusion behavior, which offer alternative pathways significantly influencing hydrogen distribution throughout the microstructure. The behavior of these dislocations is found to be highly temperature-sensitive, exhibiting distinct properties under varying thermal conditions and over extended durations. The simulation results are consistent with established models of hydrogen behavior in metallic systems and confirm that both microstructural nuances and temperature have a significant influence on hydrogen diffusion, which is in line with theoretical expectations. The insights gleaned from this research will assist in the engineering of materials that are more resilient to the deleterious effects of hydrogen penetration, thereby enhancing the safety and dependability of components operating in hydrogen-intensive environments.