High-temperature thermal expansion behaviour of C/SiC studied using an in-situ optical visualisation method and numerical simulations in a quartz lamp array heating environment

Abstract

The thermal expansion behaviour and thermal insulation performance of high-temperature structural ceramics have attracted considerable attention in the aerospace field. To further understand the high-temperature deformation behaviour and mechanism of C/SiC, an in-situ optical visualisation system was used to observe the variation in the gap width between C/SiC specimens in a quartz lamp array heating test. By using sub-pixel edge detection for the images recorded by the CCD camera and calculating the variation in gap width, it was found that the gap width first decreased and then increased during the heating process. Numerical simulations showed that the variation was caused by heat conduction and expansion of the base under the C/SiC specimens. The variation in the gap width under different working conditions was studied, and the thermal insulation performance of the specimens with and without thermal barrier coatings was compared. This work provides a new route with theoretical support for the study of the thermal expansion behaviour of high-temperature structural ceramics.