Effect of Annealing on Mechanical Properties of Mo-3Nb Single Crystal Materials

The effect of annealing on the mechanical properties for two kinds of molybdenum niobium alloying single crystal materials supplied by Russia and China were introduced. The conditions, temperature from 900 ℃ to 1 800 ℃, 2 h annealing and 4×10 -4 Pa vacuum, were chosen for both materials . The Modified Miniature Disk Test Method was adopted to examine their mechanical properties. It was found that the yield stress ( σ y)and fracture stress( σ b) were decreased with increasing the annealing temperature; however, the uniform elongation percentage δ u was increased accordingly. Compared with the original materials, approximately 20% decrease for both materials occurs for the materials after annealing at 1 600 ℃ and 1 800 ℃. It was also found that the variation of mechanical properties of the materials supplied by Russia was more obvious than that by China. The factors for causing the changes of the mechanical properties were also discussed.