The fracture behavior of cracks in the vicinity of a HIP diffusion bonded interface between JIS designation SS400 mild steel and C1100 copper was investigated. The cracks were oriented parallel to the diffusion bonded interface and a tensile load was applied in a direction perpendicular to the interface for a range of test temperatures from 20°C to -180°C. Material dissimilarity led to a complex mode of crack opening, and failure occurred either at the crack or at the material interface depending on the position of the crack relative to the interface and the test temperature. The differences in behavior were investigated using a three-dimensional finite element analysis (FEA). The strain energy density criterion was applied to predict the occurrence and direction of crack propagation by lowstress brittle fracture at extremely low temperatures. It is suggested in this paper that fracture initiation at the interface edge can be predicted based on the total strain energy density in that region.
