Effects of Porosity Distribution on the Dynamic Behavior of Two Varieties of SiC

Report No. ARL-TR-3374
Authors: Samuel R. Martin
Date/Pages: December 2004; 52 pages
Abstract: In order to understand the microstructural reasons behind variations in ballistic material properties, plate-impact tests were conducted on two sintered silicon carbides with slightly different microstructures. Regular Hexoloy (RH) and Enhanced Hexoloy (EH) were obtained from Saint-Gobain. It was determined that the porosity distribution in EH had fewer large pores leading to an 18% increase in flexural strength over that for RH. Plate-impact experiments were conducted utilizing a VISAR to measure free-surface velocities. Tests were performed on each material to determine the Hugoniot Elastic Limit (HEL) and spall strength. Spall strength was measured as a function of impact stress, and pulse duration. Results show the difference in porosity distribution between EH and RH results in no discernable difference in their HEL values and spall strengths. The spall strengths were independent of pulse width and showed a trend similar to that found in other studies for SiC. Both materials demonstrated finite spall strength above the HEL.
Distribution: Approved for public release
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Last Update / Reviewed: December 1, 2004