In this study, lanthanum oxide (La₂O₃) dispersed molybdenum (Mo–La₂O₃) alloys are fabricated using lanthanum nitrate solution and nanosized Mo particles produced by hydrogen reduction of molybdenum oxide. The effect of La₂O₃ dispersion in a Mo matrix on the fracture toughness at room temperature is demonstrated through the formation behavior of La₂O₃ from the precursor and three-point bending test using a single-edge notched bend specimen. The relative density of the Mo–0.3La₂O₃ specimen sintered by pressureless sintering is approximately 99%, and La₂O₃ with a size of hundreds of nanometers is uniformly distributed in the Mo matrix. It is also confirmed that the fracture toughness is 19.46 MPa·m^1/2, an improvement of approximately 40% over the fracture toughness of 13.50 MPa·m^1/2 on a pure-Mo specimen without La₂O₃, and this difference in the fracture toughness occurs because of the changes in fracture mode of the Mo matrix caused by the dispersion of La₂O₃.

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