Secondary phases strengthening-toughening effects in the Mo–TiC–La₂O₃ alloys

Mo–TiC–La₂O₃ molybdenum alloys were strengthened and toughened by the synergistic action of nano-carbide particles and rare earth oxides. In this paper, the Mo–TiC–La₂O₃ alloy system was prepared by powder metallurgy. The microstructure was characterized by optical, scanning, and transmission electron microscopy. The mechanical properties were tested using the hardness tester and universal tensile testing machine. The grain size of the Mo–TiC–La₂O₃ alloy is smaller than the Mo–TiC and Mo–La₂O₃ alloys. The strength and elongation of annealed Mo–TiC–La₂O₃ alloy are 1291 MPa and 6.6%, respectively. The strength and ductility of the annealed Mo–TiC–La₂O₃ alloy are higher than the Mo–TiC and Mo–La₂O₃ alloys. According to the interfacial mismatch between the secondary phases and the matrix, along with oxygen impurities interactions, the mechanisms of strengthening and toughening of the secondary phases in the Mo–TiC–La₂O₃ alloy were revealed.