Plasticity-induced crack closure (PICC) effect of small crack of notched FGH97 powder metallurgy superalloy specimen was investigated by finite element method (FEM). The influences of five principle factors

namely mesh element size

notch profile

load level

stress ratio and the constitutive model

on crack closure were analyzed. Crack propagation rate was predicted via Walker formula and compared with the test results to confirm the accuracy of FEM. The results show that crack closure level tends to converge if the size of forward plastic zone is ten times bigger than the element size around the crack tip; notch profiles affect crack closure in the closure transient zone

the load determines the crack closure stabilization level; crack closure level decreases with the increase of stress ratio till disappearance; compared with perfectly elastic-plastic constitutive model

the multi-linear elastic-plastic constitutive model shows much less dependency on mesh element size. The predicted crack propagation rate in consideration of crack closure fits well with test results.