Elastic interaction between a coherent interface and a finite crack
Journal
Physica Status Solidi (A) Applied Research
Journal Volume
158
Journal Issue
2
Pages
481-492
Date Issued
1996
Author(s)
Abstract
The elastic interaction of a finite crack with a coherent interface is investigated. In a dislocation modeling technique, a planar distribution of continuous dislocations and a planar array of discrete interface dislocations are used to simulate the crack and the interface, respectively. With lattice misfit, crack length, the distance from crack tip to interface and the geometry of the interface as the parameters, the shielding/antishielding effects arising from the interface on crack tips are discussed in details. It is found that a primary and a secondary shielding/antishielding effect on mode I and II fracture, respectively, are induced by the interface. As the interface is symmetric with the crack, the secondary effect vanishes and only the primary effect exists. If the interplanar spacing on one side of the interface, where the crack is present, is larger than that on the other side, both crack tips are shielded from mode I fracture simultaneously, and vice versa. Consequently, coherent precipitates with smaller lattice constant than the matrix become effective barriers to crack propagation. In addition, the mode I shielding/antishielding on both crack tips, which is linearly proportional to lattice misfit, becomes significant as the crack comes closer to the interface or the interface gets longer. However, with increasing crack length, the primary effect increases monotonically on the crack tip nearer to the interface, but it increases, reaches a maximum, then decreases on the other crack tip.
Publisher
Wiley-VCH Verlag
Type
journal article