C/SiCN复合材料的疲劳行为

Fatigue Behavior of C / SiCN Composite

研究了碳纤维增强非晶SiCN陶瓷基复合材料(C/SiCN)的真空拉-拉疲劳行为,对比分析了预稳定化热处理C/SiCN(HTCS)与未热处理C/SiCN(NHTCS)在疲劳后的质量、显微结构和电阻变化。结果表明,对于NHTCS试样,非晶SiCN基体的晶化造成大量气体挥发,质量损失明显;显微组织结构变化表现为基体脱落、纤维拔出、纤维断裂、裂纹扩展直至失效;电阻变化率先降后升,变化规律与材料的组织结构变化密切相关。对于预稳定化处理的HTCS试样,其质量变化、电阻变化的程度相对较小,体现出较好的预稳定化效果。

The vacuum tensile-tensile fatigue of carbon fiber reinforced amorphous SiCN matrix composite （C/ SiCN） was studied. The masses, microstructures and electrical resistances of the heat treated C/SiCN （HTCS） and untreated C/SiCN （NHTCS） were comparatively analyzed. The results indicate that it takes place dramatic mass loss for NHTCS due to crystallization of amorphous SiCN matrix ceramic. The microstructure morphologies change dra- matically and it is accompanied by matrix spalling, fiber pullout, fiber breakdown, cracks expansion and final failure. The electrical resistance change ratio drops at initial stage with the microstructure changes of C/SiCN. For NHTCS, trical resistance due to excellent pre-stabilization. of test, but increases as test goes on, which is accordant it demonstrates relatively small changes of mass and electrical resistance due to excellent pre-stabilization.