中文摘要：

以MoSi2、Ti和B4C粉为原料,采用高温热压技术合成不同体积分数TiC-TiB2增强MoSi2复合材料,研究TiC-TiB2颗粒对MoSi2基体材料显微组织、力学性能和高温氧化性能的影响。结果表明：30%TiC-TiB2/MoSi2（体积分数）复合材料的抗弯强度和维氏硬度分别达到468.3 MPa和17.07 GPa,比纯MoSi2的分别增加了63.2%和83.5%。随着TiC-TiB2体积分数的增加,复合材料的断裂方式由以沿晶断裂为主向以穿晶断裂为主转变,强化机制是细晶强化和弥散强化。在800-1 200℃氧化192 h时,30%TiC-TiB2复合材料的增质是10%TiC-TiB2复合材料的2.38-3.23倍。氧化层中没有发现低熔点的B2O3,而TiO2和SiO2的存在使材料具有较好的抗氧化性。

英文摘要：

TiC-TiB2/MoSi2 composites with different volume fractions of TiC-TiB2 particles were fabricated by hot press technology using MoSi2, Ti and B4C powders as raw materials. Effects of TiC-TiB2 particles on microstructure, mechanical properties and oxidation resistance properties of MoSi2 matrix were investigated. The results show that the flexure strength and hardness of 30%TiC-TiBE/MoSi2 composite are 468.3 MPa and 17.07 GPa, respectively. Compared with monolithic MoSi2, the flexure strength and hardness are enhanced by 63.2% and 83.5%, respectively. With the TiC-TiB2 particles content increasing, the fracture mechanism of the composites changes from intergranular fracture to transgranular fracture. The strengthening mechanisms of the composites are grain refine and dispersion strengthening. Oxidizing at 800-1 200℃, the mass gain of 30%TiC-TiB2 composites is almost 2.38-3.23 times as much as that of 10%TiC-TiB2/MoSi2 composites. Low melting glass phase of B203 can not be found in the oxidized layer, but TiO2 and SiO2 existing in the oxidation layer make TiC-TiB2/MoSi2 composites have good oxidation resistance.