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

Abstract MoSi 2 matrix composites with the addition of Mo 5 Si 3 and La 2 O 3 (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 Mo 5 Si 3 and La 2 O 3 is clearly contributive to strengthen and toughen the base. When the contents of La 2 O 3 and Mo 5 Si 3 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 MoSi 2 , and by 19.5% and 49.1% than that of 0.9 wt% La 2 O 3 /MoSi 2 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.