The Effect of Annealing on the Structure and Mechanical Properties of Mo - 47.5 Wt. % Re Alloy Sheet

The temperature dependence of microstructure, hardness, and room‐temperature tensile properties of Mo ‐ 47.5 wt. % Re sheet were measured for sheet thicknesses between 0.51 mm and 3.05 mm. Recrystallization occurred between 1200 C and 1300 C for all thicknesses, even though appreciable drops in hardness occurred at lower temperatures. The room temperature yield and ultimate strength of the alloy increased with decreasing sheet thickness and annealing temperature, while room temperature ductility decreased with decreases in these parameters. The temperature‐dependence of the tensile properties of 0.51 mm sheet was determined for samples annealed one hour at 1123 K, 1573 K, and 1873 K. The annealing practices established microstructures with differing degrees of recrystallization and second‐phase formation. The 0.51‐mm sheet did not exhibit the ductile‐brittle transition typical of unalloyed molybdenum for any of the annealing conditions in tests at temperatures as low as 77 K. These results suggest that the presence of the second phases formed during warm rolling and annealing does not adversely affect the ductility of Mo ‐ 47.5 wt. % Re for test temperatures at and below ambient, and for strain rates typical of the upper range obtained by standard tensile tests.