Dynamic failure in two-phase materials

Previous experimental research has shown that microstructural features such as interfaces, inclusions, vacancies, and heterogeneities can all act as void nucleation sites. However, it is not well understood how important these interfaces are to damage evolution and failure as a function of the surrounding parent materials. In this work, we present results on three different polycrystalline materials: (1) Cu, (2) Cu-24 wt. %Ag, and (3) Cu-15 wt. %Nb which were studied to probe the influence of bi-metal interfaces on void nucleation and growth. These materials were chosen due to the range of difference in structure and bulk properties between the two phases. The initial results suggest that when there are significant differences between the bulk properties (for example: stacking fault energy, melting temperature, etc.) the type of interface between the two parent materials does not principally control the damage nucleation and growth process. Rather, it is the “weaker” material that dictates the dynamic spall strength of the overall two-phase material.