Thermal Shock Properties of ZrB2-SiCp-Graphite and ZrB2-SiCp-AlN Ceramic Matrix Composite Material

Thermal shock property of the material can be improved by improving fracture property of the material. In this paper, factors affecting fracture property have been studied and the effect of residual stress, microstructure, strain rate and stress concentration on fracture property of material has been analyzed, which may provide help for improving thermal shock property of material. Thermal shock stability for ZrB2-SiCp-Graphite(ZSG) and ZrB2-SiCp-AlN (ZSA) was investigated by water quenching test, which indicated that ZSC may provide more stable thermal shock properties. As shown by SEM of ZSA, surface cracks appeared after it was cooled from 1200°C due to thermal shock instability of the material. Residual flexural strength of ZSA was improved by crack healing after it was cooled from 1450°C. However, no surface crack appeared for ZSG after water quenching test. This paper may provided a potential method for improving thermal shock stability of zirconium diboride ceramic matrix composites by introducing proper quantities of graphite.