Abstract:
In order to study the variation of the crack growth behavior of oxygen-sensitive materials under the interaction of creep-oxidation, the physical mechanism of dynamic embrittlement was used to establish a mathematical model of creep coupled oxidation damage. The creep-oxidation crack growth of nickel-based alloy was analyzed by Abaqus and Voronoi diagram techniques. Meanwhile, the effects of load level, grain boundary direction at initial crack, oxygen diffusion rate and creep properties on crack growth were analyzed. The results showed that the oxidation promotion effect was significant when the load was small. With the increase of load creep gradually tended to dominate. Since oxygen was easier to diffuse, the crack initiation time of straight grain boundary cracks was shorter than that of oblique grain boundary cracks. As the oxygen diffusion rate increased, the crack initiation time decreased, and the increase of load would cause the crack initiation time of the straight grain boundary cracks to stabilize. Creep constitutive parameters had almost no effect on the law of crack initiation time with load. The more difficult the materials or service conditions are to creep, the more obvious the effect of oxidation is.