Analysis of the Intergranular Cracking Process Inside Polycrystalline Heat-Resistant Materials Under Creep-Fatigue Conditions

In order to investigate the intergranular failure process in polycrystalline materials under creep-dominant fatigue, numerical simulation of inner small cracks was conducted on the basis of a simple probabilistic model. Although the simulation condition is determined from experimental observation of the cross section of specimens interrupted at different fatigue cycles, the simulation is carried out continuously and reproduces inner cracking behavior throughout the fatigue life. This enables us not only to extract the spatial distribution of inner cracks at arbitrary creep-fatigue cycles, but also to calculate the propagation rate of each inner crack.