FATIGUE CRACKING IN Ni3Al SINGLE CRYSTAL UNDER CYCLIC COMPRESSIVE LOAD
循环压缩载荷下Ni3Al基合金单晶体的疲劳开裂

Fatigue cracking in Ni3Al single crystals with two kinds of orientation was examined by means of single-edge notch specimens under cyclic compression. Stage I cracking along two or more {111} planes can occur from the notch root simultaneously. There exists an orientation dependence of the crack initiation threshold under cyclic compression. The cleavage chunk falling off from the specimen surface due to the intersection of different {111} planes was observed in (100)010] specimen, but never observed in (110)110] specimen. Subsequently, the mechanism of crack growth which is dependent on orientation was proposed in this paper.