Mechanism for void nucleation at a carbide/matrix interface

Abstract

The nucleation of a void by separation of an M₂₃C₆ carbide/α-Fe matrix interface has been studied, assuming the presence of defects which accommodate the mismatch between the two crystals. It has been shown that the only defects likely to be important are interfacial dislocations and, assuming that the radius of curvature of the carbide is accommodated by a series of small steps on the surface, an approximate analysis of vacancy-producing dislocation climb within the interface has been used to calculate a critical interfacial-stress value of 3·7 GN m⁻².