Molecular dynamics simulation of dealloyed layer-enhanced dislocation emission and crack propagation

Three-dimensions molecular dynamics (MD) method by employing the embedded atom method (EAM) potential is used to simulate the effect of stress corrosion-induced dealloyed layer existed on the surface of a crack Of Cu2Au alloy on dislocation emission and crack propagation. The simulations show that the existence of a dealloyed layer enhances dislocation emission and crack propagation, i.e., decreases the critical stress intensity for dislocation emission from K-Ie = 0.62 MPam(1/2) to K-Ie(*) = 0.556 MPam(1/2) and that for crack propagating after emitting large amounts of dislocations from K-IP = 1.14 Mpam(1/2) to K-IP(*) = 1.06 MPam(1/2). This indicates that dealloyed layer-induced tensile stress can help the applied stress to enhance dislocation emission and crack extension. (C) 2002 Elsevier Science B.V. All rights reserved.