Spall Strength of Silicon Carbide Under Normal and Simultaneous Compression-Shear Shock Wave Loading

摘要

Spall strength data of sintered and hot-pressed silicon carbide show an initial increase with an increase in the shock-induced stress to around 4 GPa. At impact stress around 6 GPa and above, spall strength data of these materials show a continuous decrease in the magnitude of spall strength. This unusual trend in the spall strength of silicon carbides may be due to the competing roles of (1) localized plasticity, (2) generation and propagation of cracks taking into consideration their relative dominance below and above a given magnitude of stress. This work presents the results of spall experiments conducted to test the relative dominance hypothesis by determining whether the observed initial increase in spall strength of silicon carbide is due to dominance of localized plastic deformation over crack-dominated brittle deformation, while the observed decline in the spall strength with an increase in the shock-induced stress reflects a dominance of crack-induced brittle deformation over plastic deformation.