Microstructure and mechanical properties of in situ SiC particulates reinforced MoSi2 matrix composite

Microstructure and mechanical properties of in situ SiC particulates reinforced MoSi2 matrix composite were investigated in this work. The results show that the microstructure of the composite consists of the beta -SiC equiaxed particulates with size of 2-5 mum, uniformly distributed in the MoSi2 matrix. A small amount of sphere pore is located within the SiC particulates. The MoSi2-SiC interface is atomically abrupt, free from amorphous phase (SiO2). The hardness, fracture toughness(K-IC), compressive strength at room temperature and flow stress at high temperature for the composite are significantly higher than those for the monolithic MoSi2. As volume percent of SiC increases, the hardness, toughness and flow stress increase, while the compressive strength at first increases and then decreases. As volume percent of SiC increases from 10 to 45, K-IC increases from 4.34 to 5.71 MPa .m(1/2), by a factor of 25%-46% than the monolithic MoSi2; At 1400 degreesC, sigma (0.2) increases from 230 to 285 MPa when SiC volume fraction increases from 20% to 45%, which corresponds to an increasing factor of 98%-146% than MoSi2.