Determination of fracture toughness for metal/polymer interfaces

This work focuses on the interpretation of experimental results obtained fr om fracture toughness tests conducted for a typical metal/polymer bimateria l interface similar to those encountered in electronic packaging applicatio ns. Test specimens,with pre-implanted interfacial cracks were subjected to a series of fracture toughness tests. Interfacial fracture toughness is int erpreted from the experimental results as the critical energy release rate (G(c)) at the instant of crack advance. The values of G(c) from the experim ents are determined using direct data reduction methods assuming linens ela stic material behavior. These G(c). values are compared to critical energy release rate values predicted by closed-form analyses of the tests, and to critical J-integral values obtained from finite-element analyses of the tes t specimen geometries. The closed-form analyses assume linens elastic mater ial behavior, while the finite-element analyses assume both linear elastic as well as elastic-plastic material behaviors.