Experimental study on flash radiation and damage characteristics of C/SiC composites induced by hypervelocity impact

摘要

Continuous carbon fiber-reinforced SiC-matrix composites(C/SiCs) have been developed for key thermal structures of aerospace and hypersonic vehicles, which is important to research on thermal and dynamic behavior of C/SiC composites under hypervelocity impact for understanding the response characteristics of C/SiC composites subjected to shock loading. The projectiles made of C/SiC composites and silicon carbide(SiC) were loaded by two-stage light gas gun to impact C/SiC plates with impact velocities from 1.35 km/s to 3.5 km/s and impact angle of 90 degrees, the damage morphology of C/SiC plates, the evolutionary process of thermal radiation and impact pressure were obtained. The experimental results show that fiber failure of C/SiC composites consumes part of the initial kinetic energy during hypervelocity impact, therefore, the carbon fiber improves the fracture toughness of SiC matrix. Under the experimental conditions given in this paper, the lower impact velocity is, the greater differences of thermal and dynamic response between the two kinds of projectiles are. Compared with SiC projectiles, the C/SiC composite projectiles have longer flash radiant duration and lower flash radiant temperature. However, when the impact velocity is higher, the flash radiant duration and the flash radiant temperature of the two kinds of projectiles are similar due to the fiber fracture of the C/SiC composite, and the peak of flash radiant temperature appears before flash radiant intensity during impact process. For the damage characteristics of C/SiC plates, the higher impact velocity is, the smaller perforation diameter of C/SiC plates is, and the shape is more regular. With the decrease of the impact velocity, the damage morphology of C/SiC plates is irregular, and the matrix powdering is more serious.