Effect of annealing temperature on La₂O₃ strengthened Mo–Re alloys

Molybdenum rhenium alloys are the solid solution strengthening alloys with high melting point and low expansion coefficient, and the addition of rare earth oxides can refine the grains and play a role in dispersion strengthening. Molybdenum−rhenium (Mo–Re) and molybdenum−rhenium−lanthanum (Mo–Re–La₂O₃) alloy plates were prepared by powder metallurgy and cross rolling method in this paper, and were annealed at different temperatures. The microstructure and room temperature tensile fracture morphology of the Mo–Re alloys and Mo–Re–La₂O₃ alloys annealed at different temperatures were observed by metallographic microscope and scanning electron microscope. The Vickers hardness and room temperature tensile properties of the two alloy plates were compared. The results show that the recrystallization temperature of Mo–Re alloys is about 1200 ℃, while that of the Mo–Re–La₂O₃ alloys is 1400 ℃. The addition of La₂O₃ increases the recrystallization temperature by about 200 ℃. With the increase of annealing temperature, the hardness and tensile strength of the Mo–Re alloys and Mo–Re–La₂O₃ alloys decrease significantly, while the elongation of Mo–Re–La₂O₃ alloys increases, up to 27.5%.