Fracture initiation in a lamellar alloy

Abstract

The possibility of slip bands providing sites for fracture initiation within composites of lamellar construction is investigated. It is proposed that the tips of these bands, which terminate at the composite's bimetallic interfaces, are the specific locations of fracture initiation. Application of a dislocation intensity factor criterion allowed the applied stress at which cracks may be initiated to be calculated. The predictions compare favorably with experimental data. The dependence of the fracture initiation stress calculated from this model is shown to follow a Hall-Petch relationship.