Toughening of MoSi2 doped by La2O3 particles

Molybdenum disilicide (MoSi2) with or without La2O3 particles were synthesized by mechanical alloying (MA) and HP techniques. The fracture toughness at room temperature was measured by Anstis’ mode and the responded microstructures were analyzed by using SEM and X-ray. The results show that the addition of La2O3 could obviously toughen the matrix. When the content of La2O3 in MoSi2 is about 0.9%, the fracture toughness value increases by about 50% more than that of pure MoSi2. We think, the corresponding toughening mechanisms depend on the following: fine-grain, microcracking, crack deflection, crack microbridging, crack bowing and branching.