DENSIFICATION MECHANISMS DURING HOT PRESSING OF ZrB2-20 VOL% SiC COMPOSITE

The dominant densification mechanisms for hot pressing of ZrB2-20 vol% SiC composite at different hot-pressing temperatures and pressures were identified. They were found to change over a very short temperature range. For hot pressing at 1700 C, the dominant densification mechanism was mechanically driven particle fragmentation and rearrangement only, whereas at 1850 C a plastic flow mechanism started to become dominant after initial particle fragmentation and rearrangement. At 2000 C, the dominant mechanism changed from plastic flow to grain boundary diffusion.