Spall strengths of sintered and hot pressed silicon carbide

Abstract

This work describes results of plane shock wave spallation experiments performed on two Silicon Carbide ceramics. One of the two SiC materials is a hot pressed ceramic manufactured by Cercom under the name SiC-B. The second SiC material is a sintered ceramic manufactured by Sohio. The densities of these materials were 3.22 Mg/m3 and 3.12 Mg/m3 for Cercom and Sohio respectively. The theoretical density of SiC is 3.21 Mg/m3. Both of these materials were tested at impact pressures up to the Hugoniot Elastic Limit of 12 GPa. The results of shock wave experiments indicate that: (1) The spall threshold of both the SiC materials tested, increased when impact stress was increased from 1.6 GPa to 3.7 GPa; (2) Above 3.7 GPa, the spall threshold decreased with an increase in impact stress to 12 GPa; (3) Both materials appear to peak in spall threshold at an impact stress of about 3.7 GPa. For example, at an impact stress of 1.6 GPa, the Cercom SiC exhibits a spall threshold of 0.90 GPa. At the stress of 3.75 GPa, th...