Crystallographic study of fatigue cracking in Ni3Al(CrB) single crystal

Abstract

The effect of crystallographic orientation on the fatigue-crack initiation and propagation in Ni 3 Al(CrB) single crystal was studied using a compact-tension specimen. Stage I crystallographic cracking and cleavage fracture were observed. Crystallographic cracking can occur on two or more {111} slip planes simultaneously. It was shown that the threshold stress intensity for crack initiation from the notch root exhibits a dependence on crystallographic orientation. In addition, an effect of orientation on microcracking behavior was also shown. The number of {111} planes intersecting with each other determines the different microscopic features on the cleavage fracture surface.