热处理对含CSiCTaCC界面C/C复合材料力学性能的影响
Effect of heat treatment on mechanical properties of C/C composites with C SiC TaC C multi-interlayers
-
摘要: 以准三维针刺炭纤维毡为预制体, 采用化学气相渗透工艺在预制体中炭纤维/基体炭之间制备C-SiC-TaC-C复合界面, 利用树脂浸渍-炭化工艺对材料进一步增密, 获得含C-SiC-TaC-C界面的C/C复合材料。研究了1400~2500℃不同温度热处理前后复合材料的微观结构和力学性能。结果表明: 热处理前, SiC-TaC界面为管状结构, 复合材料的抗弯强度为241.6 MPa, 以脆性断裂为主; 经1400~1800℃热处理后, TaC界面破坏呈颗粒状, 复合材料的平均抗弯强度下降到238.9~226.1 MPa, 其断裂方式不变, 但断裂位移由0.7 mm增至1.0 mm; 经2000~2500℃热处理后, SiC、 TaC界面均受到破坏, 复合材料平均抗弯强度急剧下降至158.7~131.8 MPa, 断裂方式由脆性断裂转变为假塑性断裂。Abstract: C-SiC-TaC-C multi-interlayers were introduced in the carbon fiber/carbon matrix interface in quasi 3D needled carbon felt by chemical vapor infiltration, the modified C/C porous performs were densified by impregnation-carbonization processes to obtain C/C composites with C-SiC-TaC-C multi-interlayers. The microstructure and mechanical properties were studied after heat treatment (HTT) at different temperatures of 1400~2500℃. The results show that the SiC-TaC interlayers have a tubular structure before HTT; while the average flexural strength of the as-prepared composites is 241.6 MPa with a brittle fracture. After HTT at 1400~1800℃, TaC interlayer is damaged to granular structure; As a result, the flexural strength of the composites declines to 238.9~226.1 MPa also with a brittle fracture, but an increasing of fracture displacement from 0.7 mm to 1.0 mm. After HTT at 2000~2500℃, both SiC and TaC interlayer are damaged. The flexural strength sharply declines to 158.7~131.8 MPa with an obvious change of fracture behavior from brittleness to pseudo-ductility.
下载: