(1. 大连理工大学 工业装备结构分析国家重点实验室，大连 116024；
2. 大连理工大学 航空航天学院，辽宁省空天飞行器前沿技术重点实验室，大连 116024)
摘 要: 以不同温度热处理纤维为增强体，以酚醛树脂为碳基体先驱体，利用先驱体浸渍裂解(PIP)工艺制备碳纤维增强碳基(C/C)复合材料。微观形貌观察发现纤维热处理能够改变C/C多孔体(经过一次裂解后)的孔隙尺寸和分布模式。力学性能测试发现，随着热处理温度提高，C/C复合材料的力学性能不断提高，对纤维进行1200 ℃热处理后，C/C弯曲强度和层间剪切强度分别提高了1.58倍和1.21倍，同时失效模式由脆性断裂转变为假塑性断裂。抗氧化性能研究发现，600 ℃热处理纤维增强材料的抗氧化性能提升，而更高温度的纤维热处理导致材料抗氧化性能下降。C/C复合材料性能变化的主要原因是热处理降低纤维表面的反应活性，使得C/C获得结合适宜的纤维/基体界面。
关键字: C/C复合材料；热处理；力学性能；抗氧化性能
（1. State Key Laboratory of Structural Analyses for Industrial Equipment, Dalian University of Technology, Dalian 116024, China;
2. School of Aeronautics and Astronautics,Liaoning Provincial Key Laboratory of Advanced Technology for Aerospace Vehicle,Dalian University of Technology, Dalian 116024, China）
Abstract:Carbon fiber reinforced carbon matrix composites (C/C) were prepared by precursor impregnation pyrolysis (PIP) method, carbon fibers heat-treated at different temperatures were used as reinforcement, phenolic resin was used as carbon precursor. The results show that the size and distribution pattern of pores in porous preform (after primary cracking) are changed, according to micromorphology observation. Mechanical properties of C/C composites are improved with the increase of heat treatment temperature. Flexural strength and interlaminar shear strength of C/C increase by 1.58-fold and 1.21-fold after fibers heat-treated at 1200 ℃. With the heat treatment temperature rising, the fracture mode of C/C is changed from brittle to pseudoplastic. Oxidation resistance of 600 ℃ heat-treated fiber reinforced composite is improved, while those of 1200 ℃ and 1500 ℃ heat-treated fiber reinforced composites decrease. The property of C/C is changed because heat treatment reduces the surface activity of fibers, so C/C composite has a suitable interface.
Key words: C/C composites; heat treatment; mechanical property; oxidation resistance
