Dynamic strength and fragmentation of silicon carbide

Abstract

This study investigates the rate-dependent compressive failure and fragmentation of two armor ceramics. Specifically, the uniaxial compressive response of two formulations of silicon carbide, SiC-N and SiC-X1, have been investigated at quasi-static rates of 10-4 s-1, using a universal testing machine, and dynamic rates of 102 s-1, using a Kolsky (split-Hopkinson) bar. The loading and failure have been investigated using high-speed imaging and Digital Image Correlation (DIC). Fragmentation has been shown to be an important factor in understanding the performance of advanced ceramics. Consequently, the dynamic fragments from individual experiments of each formulation have been quantified for their cumulative size distributions. Results from the compression experiments suggest that SiC-N and SiC-X1 have statistically comparable strengths of over 4 GPa, at both quasi-static and dynamic rates, with both materials exhibiting a slight compressive strength rate-sensitivity. Results from the high-speed imaging show that the failure mode of SiC-N and resulting fragment morphology match previously reported experiments in literature. However interestingly, SiC-X1 exhibits a clear shift to a lower average fragment size, likely due to microstructural features.