Hierarchical Diamond-Based Ceramic Composites

An innovative combination of experimental synthesis and testing and multiscale simulation techniques explored the effects of hierarchical microstructure (mesoscale diamond packing and nanoscale interfaces) on the mechanical and ballistic performance of diamond-silicon carbide (SiC) composite ceramics.

Army Research Laboratory, Aberdeen Proving Ground, Maryland

This research developed and utilized advanced processing, modeling, and micromechanical tools to discover and demonstrate hierarchically structured diamond-based composites with exceptional mechanical and ballistic behavior. Understanding how nanoscale and mesoscale microstructural features in diamond-silicon carbide (SiC) composites influenced the physics of failure was critical in uncovering ways to improve performance for soldier protection and discover potential defeat mechanisms.

Emphasis was placed on the fundamental understanding of the deformation and failure mechanisms, which enabled the design and development of robust materials to support Army core functions. Development of new materials was the focus with specific emphasis on fundamental knowledge of microstructural grain boundaries in diamond-SiC composites. Novel processing routes to selectively tailor the nano-mesoscale microstructure in heterogeneous ceramic armors were explored via conventional hot-pressing, reactive hot-pressing, and spark plasma sintering (SPS). Correlations between the nano-mesoscale hierarchical microstructure, deformation mechanisms, and mechanical response were explored using advanced characterization methods and small-scale mechanical testing. Higher fidelity mesoscale mechanics models were sought by using experimentally obtained microstructural information coupled with atomistic models of relevant grain boundary interfaces.