Abstract
The purpose of this study is to investigate low cycle fatigue (LCF) strength, crack initiation and crack growth behavior of Ni based superalloy Alloy246. As the result of the observation of etched specimen, grain size is from 3 to 5 mm. LCF test is conducted under load controlled conditions. Small cracks initiate at the first cycle of low cycle fatigue and grow with coalescence. Small cracks propagate along slip direction. The result of fracture mechanics evaluation shows crack growth rate along dendritic structure is higher than that along slip direction. As the result of EBSD, crack growth direction corresponds to slip plane. Small cracks initiate near grain boundary. Small cracks initiate under stress of 100 MPa.
