The mechanism of ductile fracture in constrained thin silver films

The mechanisms of ductile fracture in pure sih;ef under various high-triaxi al stresses in constrained thin silver films were investigated. New experim ents and analyses have been performed that have both improved and extended the findings of earlier work by the authors. Particular emphasis was placed on investigating ductile fracture by unstable cavity growth. Here, cavitie s grow without the necessity for continual increase in flow stress and with out substantial far-field plastic strain. This mechanism was recently descr ibed by Huang, Hutchinson and Tvergaard. Improvements in the analysis of un stable cavity growth included direct determination of the stress states for cavity instability with FEA analysis using more accurate determinations of the stress states within the interlayer, the consideration of cavity-cavit y interaction, residual stresses and elastic incompatibility stresses acros s interfaces. Ductile fracture under high-triaxial stresses, associated wit h low macroscopic strains, appears to be explained by unstable cavity growt h. (C) 1998 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All r ights reserved.