空间紫外辐射侵蚀环境下SiC/(Cf/SiC)陶瓷基复合材料的服役特性演变规律OA北大核心CSTPCD

SiC/(Cf/SiC)ceramic matrix composites were respectively irradiated for 0,10,30,60 and 120 h under ultraviolet irradiation environment with ultraviolet wavelengths of 200～400 nm,minimum temperature of-50℃and radiation level of 3.0 W/m2.The effects of ultraviolet irradiation service environment on SiC/(Cf/SiC)ceramic matrix composites were investigated in con-junction with the evolution of microstructure,components and mechanical properties.The results show that compared with those of SiC/(Cf/SiC)ceramic matrix composites without UV irradiation,the flexural strength and modulus of SiC/(Cf/SiC)ceramic matrix composites after UV irradiation for 10 h increase slightly.After UV irradiation for more than 30 h,with the further increase of irradia-tion time,its flexural strength increases first and then decreases,while the flexural modulus continue to decrease,the surface crack defects of SiC/(Cf/SiC)ceramic matrix composites show an increasing tendency about crack size and number,indicating that ultra-violet radiation further damage the inner layer of the material.The SiC/(Cf/SiC)ceramic matrix composites before and after ultravi-olet radiation presents a step-like flexural fracture behavior.However,the fracture of the sample without UV radiation is dominated by fiber fracture.The fracture morphology of the sample with UV radiation for 10 h is similar to that of the un-irradiated sample,and the fiber is not obviously eroded.After 30 h of ultraviolet radiation,in addition to carbon fiber fracture,obvious carbon fiber pull-out and interface layer exfoliation can also be found in the fracture section of the sample,and the corrosion effect of carbon fiber is obvious.After 120 h of ultraviolet radiation,the erosion of carbon fiber in SiC/(Cf/SiC)ceramic matrix composites is further aggravated,the interface layer peeling is serious,and the end of carbon fiber presents a needle-like structure.