【摘要】 以Mo粉、Si粉和C粉为原料,采用原位反应热压一次复合工艺制备不同含量SiC颗粒增强的SiCp/MoSi2试样,并研究其室温抗弯强度、断裂韧性、相对密度以及显微组织。结果表明,原位反应热压一次复合工艺制备的SiCp/MoSi2复合材料的强韧性比纯MoSi2有了大幅度的提高,当SiC含量为40vol%时,SiCp/MoSi2复合材料的抗弯强度达到最大,为475.2MPa,当SiC含量为50vol%时,复合材料的断裂韧性达到最大,为5.45MPa.m1/2。原位形成的SiC使MoSi2基体晶粒得到明显细化,并减少和消除了脆性的SiO2玻璃相。SiCp/MoSi2复合材料强韧性的提高主要是由于晶粒细化、SiC颗粒弥散强化以及脆性SiO2玻璃相的减少和消除。更多还原

【Abstract】 SiC_p/MoSi₂ composites with different volume fraction of SiC were prepared by the technique of in situ synthesizing and hot-pressing the pure powder of Mo,Si and C.The bend strength,fracture toughness and relative density of the composites were measured and the microstructure was observed.It is found that the strength and toughness of the composites are increased compared with those of mono MoSi₂ material.The maximum bend strength of 475.2MPa in the composite with 40vol%SiC and the maximum fracture toughness of 5.45 MPam^1/2 in the composite with 50vol%SiC are obtained.It is observed that the in situ formed SiC particles refine the MoSi₂ grains and eliminate the brittle SiO₂ glass phase.The increase of the strength and toughness of SiC_p/MoSi₂ composites is mainly attributed to the refinement of MoSi₂ grains,dispersion strengthening of the SiC particles and elimination of the brittle SiO₂ glass phase.更多还原