MICROCRACK INITIATION AT TIP OF A RIGID LINE INHOMOGENEITY

A dislocation emission mechanism for microcrack initiation at tip of a rigid Line inhomogeneity is proposed in the present paper. For a rigi d line inhomogeneity embedded in a ductile matrix, it has been observe d that dislocations of one sign are driven away from the tip due to hi gh stress level; while the stationary dislocations of the opposite sig n are left behind near the tip of the line inhomogeneity. As the resul t, a Zener-Stroh crack is initiated at the tip of the inhomogeneity. A very interesting and important result that emerged from the analysis is that the critical stress intensity factor for a line inhomogeneity can be related to the fracture toughness of a crack in the same materi al.