Fabrication and wear characteristics of MoSi2 matrix composites reinforced by La2O3 and Mo5Si3

MoSi2 matrix composites with the addition of Mo5Si3 and La2O3 (LMM) were fabricated by self-propagating high-temperature synthesis (SHS) and sintering technique. These composites were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results shows addition of both Mo5Si3 and La2O3 is clearly contributive to strengthen and toughen the base. When the contents of La2O3 and Mo5Si3 are 0.9 wt% and 5 at.%, respectively, the hardness and fracture toughness of the LMM are increased independently by 36.1% and 99.1% than that of pure MoSi2, and by 19.5% and 49.1% than that of 0.9 wt% La2O3/MoSi2 composite. The toughening mechanism of the composite includes fine crystal and crack microbridging. This composite exhibits excellent wear resistance. Its wear mechanism has been observed to be adhesion, oxidation and brittle fracture during dry slide wear test against carbon steel.