Deformation processes in refractory metals

A report is presented of yield point return studies on alloys of niobium containing both oxygen and hydrogen. Here it has been observed that hydrogen has a complex effect on both the kinetics and energetics of the oxygen yield point return in niobium. Work in the area of slow strain-rate embrittlement of oxygen by niobium and its relation to dynamic strain-aging is described, along with data that has been obtained for the diffusion of oxygen and nitrogen in tantalum. They compliment similar data already published on the diffusion of oxygen and nitrogen in both niobium and vanadium. Finally, a report of the preliminary work of a study of the effects of hydrogen on both slow strain-rate embrittlement and dynamic strain aging in vanadium is presented. Because the embrittling effect of hydrogen can seriously reduce the tensile ductility it is not possible to study most aspects of dynamic strain aging using tension tests. Compression tests on the other hand do not suffer from this problem