Effects of temperature on flexural behavior and flaw sensitivity of ZrB2-SiC-graphite composite

Abstract A high temperature damage model was presented to investigate the flexural behavior and flaw sensitivity of ZrB 2 -SiC-graphite composite at high temperatures. This high temperature damage model combined an asymmetry between tension and compression, and effects of temperature and mechanical load. Room temperature tensile modulus, compressive modulus and fracture loads at different temperatures were measured by experimental tests. Experimental results show that tensile modulus is 1.2 times for compressive modulus in the direction parallel to graphite flake. Moreover, the fracture load of ZrB 2 -SiC-graphite composite measured by three-point bending method has obvious temperature dependence. These above experimental results were applied to simulate the high temperature flexural behavior. Numerical results declare that the temperature has great effect on the fracture strength and mechanical damage of ZrB 2 -SiC-graphite composite. With the increase of temperature, the maximum stress and mechanical damage exhibit less sensitive to the crack length above the brittle-ductile transition temperature (1300 °C).