SiC/MoSi_2纳米复合材料的显微结构与力学性能

Microstructure and mechanical properties of SiC/MoSi_2 nanocomposites

以Mo、Si和聚碳硅烷为原料,采用先驱体转化-反应热压制备SiC/MoSi2纳米复合材料,并研究纳米SiC体积分数对材料显微结构和力学性能的影响。结果表明,所制备的纳米复合材料中含有MoSi2、SiC和极少量的Mo5Si3及SiO2。纳米SiC的引入显著地改善了材料的力学性能,15%SiC/MoSi2纳米复合材料的综合力学性能最好,其室温抗弯强度和断裂韧性分别为610MPa和4.90MPa/m1/2,比纯MoSi2试样的分别增加了141.1%和58.0%;其高温抗弯强度在1200和1300℃时分别为720和516MPa。

Using polycarbosilane,Mo and Si powders as raw materials,SiC/MoSi2 nanocomposites were fabricated by precursor conversion and reactive hot pressing.The effects of volume fraction of SiC nanoparticles on the mechanical properties and microstructure of SiC/MoSi2 nanocomposites were studied.The results show that the nanocomposites obtained consist of MoSi2,SiC,less Mo5Si3 and SiO2.The mechanical properties of the nanocomposites are dramatically improved by incorporating of SiC nanoparticles.15%SiC/MoSi2 nanocomposite has the best comprehensive mechanical properties,with the flexural strength and fracture toughness of 610 MPa and 4.90 MPa/m1/2 at room temperature,which are increased by 141.1% and 58.0% compared with those of MoSi2,respectively.Its flexural strengths at 1 200 and 1 300 ℃ are 720 and 516 MPa,respectively.