Prediction of low-cycle crack initiation life of powder superalloyFGH96 with inclusions based on damage mechanics
(1. School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China;
2. AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China)
2. AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China)
Abstract: The effects of inclusions in powder superalloy FGH96 on low-cycle fatigue life were studied, and a low-cycle crack initiation life prediction model based on the theory of damage mechanics was proposed. The damage characterization parameter was proposed after the construction of damage evolution equations. Fatigue tests of the powder superalloy specimens with and without inclusion were conducted at 530 and 600 °C, and the model verification was carried out for specimens with elliptical, semi-elliptical, polygon and strip-shaped surface/subsurface inclusion. The stress analysis was performed by finite element simulation and the predicted life was calculated. The results showed a satisfying agreement between predicted and experimental life.
Key words: powder superalloy FGH96; low-cycle fatigue; inclusion; crack initiation life prediction; damage mechanics