Mechanical properties of monocrystals of molybdenum and its alloys at high temperatures

The effect of small carbide-forming Nb and Zr additions in combination with carbon on mechanical properties of molybdenum monocrystals was studied. Sample tests on short-range high-temperature strength and creep were conducted. It is shown that small amounts of alloying additions (0.05-1.0 at.%) of carbide-forming Zr and Nb elements in combination with 0.05-0.2 at.% of C increase heat resistant and creep properties of molybdenum monocrystals at 1630 and 1870 K. Monocrystals with Zr and C additions have the highest mechanical characteristics. Introduction of small amounts promoting the appearance of cellular-fibrous structure increases creep resistance at the expense of interaction of moving dislocations with soluted atoms and microsegregations and also at the expense of increasing barrier role of dislocation subboundaries in the process of crystallization and creep