In situ fabrication and properties of 0.4MoB-0.1SiC-xMoSi2 composites by self-propagating synthesis and hot-press sintering

Mo, Si and B 4 C powders were used to fabricate 0.4MoB-0.1SiC- x MoSi 2 composites by self-propagating high-temperature synthesis (SHS) and hot pressing (HP). The effects of MoSi 2 content ( x = 1, 0.75, 0.5 and 0.25) on phase composition, microstructure and properties of the composites were investigated. The results showed that the 0.4MoB-0.1SiC- x MoSi 2 composite exhibited Vickers hardness of 10.7–15.2   GPa, bending strength of 337–827   MPa and fracture toughness of 4.9–7.0   MPa   m 1/2 . The fracture toughness increased with the increasing volume fraction of MoB and SiC particles which were promoted by the toughening mechanisms, such as crack bridging, cracks deflection and crack branching. Moreover, the electrical resistivity showed an increasing trend with decreasing volume fraction of MoSi 2 .