Phase equilibria in the ternary system of vanadium--molybdenum--zirconium

Cast and annealed alloys of the V--Mo-- Zr system were investigated by the methods of metallography and x rays, and by determining the temperatures of initial melting. It was found that ZrMo/sub 2/ and ZrV/sub 2/ form a continuous series of solid solutions with a cubic structure of the type MgCu/sub 2/ ( lambda /sub 2/). The lambda /sub 2/ phase is formed by a peritectic reaction from a molten liquid and a metallic solid solution based on V + Mo ( alpha ). The temperature of the threephase equilibrium L + alpha in equilibrium lambda / sub 2/ decreases from 1900 deg C on the molybdenum-zirconium side to 1290 deg C on the vanadium-zirconium side. In the region Zr-- ZrMo/sub 2/-- ZrV/sub 2/ crystallization begins with separation of alpha , lambda /sub 2/ or BETA , depending on the composition, and is completed by solidification of excess liquid in the form of a mixture of BETA + lambda /sub 2/. The temperature of the three-phase equilibrium L #EM BETA + lambda /sub 2/ decreases from 1560 deg C on the zirconium- molybdenum side to 1230 deg C on the zirconium-vanadium side. Below the solidus lambda /sub 2/ is inmore » equilibrium with alpha (in the region Mo--V-- ZrV/sub 2/-- ZrMo/sub 2/) or with a solid solution on a base of BETA - Zr (in the region Zr-- ZrMo/sub 2/ZrV/sub 2/). The solubility of zirconium in V + Mo and of V + Mo in BETA zirconium decreases with increasing ratio of V: Mo and with decreasing temperature. (tr-auth)« less