Dynamic Compressive Properties of 2D-C/SiC Composites under Low Temperature

摘要

The dynamic compressive experiments of 2D-C/SiC composites under low temperature were performed on the SHPB system. The low temperatures at 173K and 103K were obtained by controlling the ratio of the absolute alcohol to the liquid nitrogen. The wave shapers were designed to meet the requirements of stress uniformity and constant strain rate in SHPB setup. The experimental results show that the 2D-C/SiC composites exhibit pseudo-plastic behaviors under dynamic loading and low temperature conditions for the micro cracks in the composite. The significant strain softening of the specimens occurred instead of the typical brittle failure when the stress exceeded the compressive strength in the test, and the specimens have experienced a large deformation before the final failure. The dynamic compressive strength of the composites increased with decrease of temperature, however the failure strain decreased. The strength of the interface between internal fibers and matrix in the 2D-C/SiC composites enhanced at low temperatures, resulting in the higher compressive strength of the composites.