2D-SiC/SiC 复合材料的弹丸冲击损伤及冲击后拉伸性能

Continuous fiber-reinforced ceramic matrix composites are widely used for high temperature components like aerospace engines due to their superior performance at elevated temperature. However, these materials are susceptible to damage from foreign object debris during service, which has become a significant concern. To investigate the impact damage characteristics of 2D-SiC/SiC composites, this study utilized a light gas gun to subject specimens prepared using chemical vapor infiltration (CVI) technology to ballistic impact. The impact processes were recorded with a high-speed camera, while the surface and internal structures of foreign object damage (FOD) were examined by optical microscopy and computed tomography (CT). This investigation revealed that conical cracks, interlaminar delamination, fiber fracture, and matrix collapse were the primary manifestations of high-speed impact damage. Damage characterization indicated that backside damage and edge delamination damage were caused by reflected tensile waves. As the impact velocity increased, the combined action of the projectile and tensile waves resulted in specimen penetration and weakening of edge delamination damage. Quasi-static tensile tests on high-speed impact specimens elucidated the relationship between residual mechanical properties and impact velocity, as well as projectile diameter. The results showed that residual tensile strength was a crucial parameter indicative of the severity of impact damage. Additionally, digital image correlation (DIC) was employed to determine strain distribution during tensile processes. By integrating residual tensile strength after impact with different projectile diameters and impact velocities, the study further explored the effect of varied parameters on impact damage. The research findings highlighted that projectile diameter as the primary factor influencing the extent of high-speed impact damage.