Fracture toughness for interfacial delamination of Cr–Mo steel multilayer laminate

Abstract

Interface toughness for delamination has been determined in a laminate composite consisting of Fe–0·9Cr–0·5Mo steel layers. Three point bend tests were used to evaluate the critical energy release rate Gc for delamination under elastic linear and plane strain conditions. A value of Gc of 2·8 kJ m−2 was obtained which is considerably lower than the energy for crack propagation across the layer. The given Gc corresponds to a critical stress intensity factor Kc of 25 MPa m1/2. These low values are responsible of delamination and, therefore, of the 34% improvement in toughness of the laminate with regard to the monolithic material.