Thermal Shock and Residual Strength Testing of SiC/SiC Composite Braided Tubes

Background: Ceramic matrix composites are promising materials for high temperature application in aerospace and nuclear engineering. In these applications, thermal shock is an important potential cause for failure. Objective: In order to study thermal shock resistance of SiC/SiC composite braided tubes, a novel method has been developed to apply thermal shock cycles to tube sections and then measure the residual tensile strength. Methods: SiC/SiC composite braided tubes have been thermally shocked by many cycles in a short time using a novel test platform based on quartz lamp irradiation heating. The circumferential tensile strength was measured using C-ring specimens after thermal shock testing of short tube sections. Numerical simulations of the stress from the thermal shock test were conducted using the finite element method. Results: The circumferential tensile strength decreased with increasing number of thermal shock cycles in air. An embrittled region with limited fiber pullout due to oxidation extended from the surface. Conclusions: The test platform can simulate service environments with fast temperature cycling for small test specimens in air.