【摘要】 本工作以AlN和Y2 O3为烧结助剂 ,采用先驱体转化 -热压烧结的方法制备出了Cf/SiC复合材料 .研究了纤维类型影响复合材料力学性能的本质原因 .由于T3 0 0纤维的制备温度明显低于M 40JB纤维的制备温度 ,因此 ,与M 40JB纤维相比 ,T3 0 0纤维的石墨化程度较低且含有较多的杂质 ,从而导致T3 0 0纤维表面的活性强 ,而M 40JB纤维表面的活性较弱 .正是这种结构和成分的差别 ,使T3 0 0纤维与基体的结合较强 ,而M40JB纤维与基体的结合较弱 ,因此以T3 0 0纤维为增强相的复合材料呈现脆性断裂 ,而以M 40JB纤维为增强相的复合材料则呈现韧性断裂 ,该复合材料具有较好的力学性能更多还原

【Abstract】 The effect of fiber type on mechanical properties of C f/SiC composites prepared by precursor pyrolysis followed by hot pres_sing was investigated. It is found that fiber T300, heat treated at temperature below 1500 ℃, has a lower degree of graphitization and consisted of more impurities compared with fiber M40JB, heat treated at temperature over 2 000 ℃, suggesting that fiber T300 has much higher chemical activity than fiber M40JB. Therefore, the composite with fiber T300 shows brittle fracture behavior, mainly due to the strongly bonded fiber/matrix interface as well as the degradation of fiber during the preparation of the composite. The composite with fiber M40JB exhibits tough fracture behavior, mainly due to the relatively weakly bonded fiber/matrix interface and higher strength retention of the fiber. The results also show that highly graphitized carbon fiber is more suitable to prepare C f/SiC composites.更多还原