Morphological effect of retained austenite microstructure on hydrogen diffusion under contact loading of bearings

Hydrogen diffusion within bearings presents a significant risk for the development of white etching cracks. This study investigates the impact of the morphological effect of austenite on hydrogen diffusion behavior under contact loading using the finite element method. Our findings reveal that horizontal lamellar austenite exhibits a superior capacity for trapping hydrogen. The presence of horizontal lamellar austenite leads to a more pronounced reduction of stress within martensite. The stress states of various austenite morphologies potentially influence hydrogen diffusion properties. Moreover, hydrogen diffusivity is significantly reduced by horizontal lamellar austenite. This reduction is related to the effective area of austenite, which is defined as the area perpendicular to the direction of hydrogen diffusion. Austenite with various morphologies intrinsically serves as a hydrogen trap and directly affects hydrogen diffusivity. These results highlight the effects of austenite morphology on hydrogen diffusion, encompassing both intrinsic and extrinsic influences.