Identification of a Beta-Tungsten Phase in Tungsten–Rhenium Alloys

Abstract

PHASE diagram equilibrium studies in the binary tungsten–rhenium system show the presence of two phases over the range 0–65 wt. per cent rhenium at 1,500° C (ref. 1). A terminal solid solution having a body-centred cubic structure exists from 0 to about 27 wt. per cent rhenium, and a phase having a tetragonal sigma-type structure is found in the composition range 43–65 wt. per cent rhenium. In this investigation, alloys containing 13–45 wt. per cent rhenium prepared by vapour deposition at 500° C were found to contain a phase having a β-tungsten type structure not previously reported in tungsten–rhenium alloys. The stability of this phase with respect to temperature and composition is now being examined. No evidence for the presence of sigma phase or elemental rhenium was found in these alloys as deposited.