A New Method for Determining Strength and Fracture Toughness of Ceramic Materials in Air at 1500-2000°C

摘要

Evaluation of the mechanical properties at ultra-high temperatures for ceramic composites is necessary and important for the safety of designing the ceramic components. In this work, a new and novel test method named as local ultra-high temperature together with applied load method (LUHTAL), was developed to determine the tensile, compressive, bending strength and fracture toughness of ceramic composites. The four point bending load was conducted to measure the bending strength and fracture toughness of ceramic composites after the center of the sample was heated up to about 1500-2000°C by oxygen-assisted spray combustion. To check the availability and reliability for this method, typical ceramic materials including ZrB_2/SiC and C/SiC fiber reinforced composite coated with Si, were used as the testing samples. It is indicated that this method is good and feasible for evaluating the mechanical properties of the ceramic composite at ultra-high temperatures in air.