AN INVESTIGATION OF VANADIUM-TECHNETIUM ALLOY SYSTEM

A phase diagram has been determined for the vanadium-technetium alloy system using the following techniques: metallography, X-ray diffraction, electrical resistivity measurements, electron-probe microanalysis of a diffusion couple, microhardness measurements, and solidus point determinations. In addition to the terminal phases, three intermediate phases are observed in this alloy system. There is a phase centered about 50% Tc having the ordered b.c.c. (CsCl-type) structure and two phases of higher technetium content, (δ and γ), which exist above 1150 °C. The structures of these phases were not determined, but it is proposed that they are also related to a b.c.c. lattice. Precise lattice parameter, electrical resistivity, and microhardness data are presented. Eutectoid decomposition of the δ phase was examined by metallography and microhardness measurements. Implications of metallurgical variations on the superconducting properties of these alloys are discussed. © 1968.