THE INTERFACIAL MISFIT DISLOCATION NETWORKS IN A DS CASTING NI3AL BASE ALLOY IC6

The interfacial misfit dislocation networks (IMDN) in an unidirectiona lly-solidified (DS) casting Ni3Al base alloy IC6 have been investigate d by means of scanning electron microscopy (SEM), transmission electro n microscopy (TEM) and stress-field analysis. It is found that the IMD N is composed of the edge dislocations with the Burgers vectors a/2[11 0] and a[100] on the {001} gamma/gamma' interface. The effective stres s field is within the limit of 10-20 nm. The density of the IMDNs is a round 15-20 nm/N, depending on the heat-treatment conditions and defor mation conditions of the specimen. The existence of the IMDNs effectiv ely exhibits the motion of moving dislocations during deformation.