Response of Bulk Cu-Nb Nanolamellar Composites to Severe Rolling Strains

Abstract

In bulk multi-phase composite metals containing an unusually high density of heterophase interfaces, the bi-metal interface controls all defect-related processes. Quite unconventionally, the constituent phases play only a secondary role. With the ‘right’ characteristics, these bi-material interfaces can possess significantly enhanced abilities to absorb and eliminate defects. [1-3] Through their unparalleled ability to mitigate damage accumulation induced under severe loading and/or severe environments, they will provide their parent composite with a highly effective healing mechanism and consequently a robustness not possible in existing advanced structural materials. Today’s bulk synthesis techniques and materials models, however, are unprepared to treat materials that are dominated by bi-metal interfaces. Consequently we cannot fabricate interface-dominant composites with the needed interfacial properties. In this work, we approach this problem by developing a predictive and experimentally validated model that holds the unique capability to predict the evolution of the interfacial structure and behavior during bulk large strain deformation. To succeed in this pioneering effort, we will spearhead new and creative ways to overcome the areas in which current methodologies are the weakest—in linking length scales over the so-called ‘micron gap’ and accounting for the special roles of bi-metal interfaces. This innovative multi-scale predictive capability will for the first time offer a tool to address materials falling within the new paradigm of interface dominance and to predict the synthesis routes needed for a targeted set of desired interfacial properties