Mechanical behavior of C/SiC composites under hypervelocity impact at different temperatures: Micro-structures, damage and mechanisms

To understand the mechanical behavior of C/SiC composites under hypervelocity impact at different temperatures, impact tests are conducted using a modified electrical gun, and corresponding numerical simulations are implemented. In addition, the decrease of residual strength induced by damage is also measured after impact tests. Tensile and shear failures occur in different regions of fracture, and the damage zone around the fracture is very confined (<5 mm). Besides, the distribution of debris clouds shows "three zones" mode, forming with different mechanisms, and demonstrates that there is a high-energy powdering column in the centre zone. As for the diameter of penetration hole, it increases with impact velocity. At low temperature, with the change of mechanical properties and forming of new micro-cracks, the fracture is smoother, while the diameters of damage zone and penetration hole are smaller. Furthermore, the damage induced by hypervelocity impact significantly reduces the strength of C/SiC composites.