Evaluation of the deformation fields and bond integrity of Cu/SS joints

The stress states that lead to failure of joints between Glidcop™ CuAl25 and 316L SS were examined using finite element modeling techniques to explain experimental observations of behavior of those joints. The joints were formed by hot isostatic pressing (HIP) and bend bar specimens were fabricated with the joint inclined 45° to the major axis of the specimen. The lower surface of the bend bar was notched in order to help induce a precrack for subsequent loading in bending. The precrack was intended to localize a high stress concentration in close proximity to the interface so that its behavior could be examined without complicating factors from the bulk materials and the specimen configuration. Preparatory work to grow acceptable precracks caused the specimen to fail prematurely while the precrack was still progressing into the specimen toward the interface. The finite element model demonstrated maximum stress concentrations in the interface layer to be shifted off-center. An additional benefit from the finite element modeling effort was in understanding if the stress states in this non-conventional specimen were representative of those that might be experienced in practice.