9522206 Kassner The ductile fracture Mechanisms of constrained metals will be studied using an integrated mechanics-materials science approach. Common engineering situations involving constrained metals are thin interlayers such as welds and brazes, metal interconnects in integrated circuits and some composites. Current theories for ductile fracture are generally based on cavity growth which in turn require unrealistically large plastic strains. two new cavity expansion models that do not require macroplasticity or cavity nuclei coalescence based mechanisms appear to be more reasonable. High triaxial stress states will be studies using silver interlayer specimens that are free of bulk defects. Changes in the void microstructure of the interlayer will be examined at small plastic strains via the scanning electron microscope and high voltage transmission electron microscopy. ***