Cracking behavior of ZrB2-SiC-Graphite sharp leading edges during thermal shock.

Crack initiation and propagation of ZrB 2 -SiC-Graphite (ZSG) sharp leading edges (SLEs) subjected to thermal shock were systematically evaluated by the water spraying method followed by a crack dyeing treatment. Distinct differences in the crack patterns among different test conditions were observed, and the cracking behavior of ZSG SLEs (including crack initiation time, crack number and critical failure temperature) was revealed to be strongly dependent on both the cooling rate and the microstructure. The crack propagation during thermal shock could be considered as a quasistatic process (crack speed was lower than 1 cm/s) that needed to be driven by continuous cooling. [ABSTRACT FROM AUTHOR]