石英纤维织物增强氮化物陶瓷基复合材料的性能(英文)

PERFORMANCE OF BRAIDED SILICA FIBER-REINFORCED NITRIDE-BASED CERAMIC COMPOSITES

采用先驱体转化法制备了2.5维石英纤维织物增强氮化物陶瓷基复合材料。对所制备材料的力学性能、热物理性能、烧蚀性能和断口显微形貌进行了研究。研究了裂解温度及纤维体积含量对复合材料抗弯强度的影响。结果表明:该材料具有较好的力学性能和优良的抗烧蚀性能,随着纤维体积含量的提高,复合材料的抗弯强度随之提高。当纤维体积分数为48%,裂解温度为800℃时,复合材料显示出最高径向抗弯强度(134.6MPa)。烧蚀过程中无分层和剥离现象,表面平整,线烧蚀率为0.038mm/s。材料的增韧机制是基体与纤维界面的脱粘和纤维的拔出吸收了大量的能量。

Using the polymeric precursor impregnation and pyrolysis method, 2.5-dimensional braided silica fiber-reinforced nitride-based composites （2.SD-SRNCs） were prepared. The mechanical properties, thermal properties, and ablative properties of the 2.5D-SRNCs were evaluated. The effect of silica fiber volume content and pyrolysis temperature on the flexural strength of the 2.5D-SRNCs was studied. The composites have better mechenical and ablative resistant properties. The results show that flexural strength increases with the increase of fiber volume content and decreases with the increase of pyrolysis temperature. The longitude flexural strength of the 2.5D-SRNCs reach the maximum value （134.6 MPa） with a fiber volume content of 48% and pyrolysis temperature of 800 ℃. The 2.5D-SRNCs have a low linear ablation rate of 0.038 mm/s and no fused layer accumulation or delamination was found on the ablation surface. The pseudoplasticity and toughening of the 2.5D-SRNCs occur by the mechanism of the absorption of much fracture energy by the fiber/matrix interface debonding and the pulling out of fiber.