3.2. Mechanical properties
The mechanical properties of composites are given in Table 2. For comparison, monolithic MoSi2 has also been prepared during same process as SiC/(Mo, W)Si2 composites from SHSed powder. Except in MWSC3, which relative density is quite low, significant improvement in hardness has been obtained by incorporation SiC into (Mo, W)Si2. This may be due to the high hardness of SiC compared to that of (Mo, W)Si2. Table 2 also shows the flexural strength and fracture toughness results of SiC/(Mo, W)Si2 composites and monolithic MoSi2 at room temperature. The values of flexural strength and fracture toughness decrease when the volume fraction of WSi2 increases from 5% to 15%, which could be contributed to the decrease of relative density of composites. The flexural strength and fracture toughness results of MWSC1 composite are 253.3 MPa and 9.43 MPa m1/2, increased by approximately 86.9% and 124.5% as compared to MoSi2 matrix, respectively. It can be concluded that the addition of SiC and WSi2 via in situ process significantly improved the mechanical properties of the MoSi2.
Table 2.