Yield Behavior of Polycrystalline Niobium

Abstract

The yield behavior of niobium (columbium) has been studied under conditions of different states of stress, temperatures and strain rates, material compositions, and microstructures. Using data gathered in the present investigation as well as that obtained from ten other sources, it is shown that a relationship including the foregoing variables is given by γ̇G=Ae−[ΔH*−V(τG−τiG)]/RT While details of the frequency factor A remain unclear, it appears that it may be treated as a constant over a wide range of temperatures and strain rates. The analysis included in this paper shows that a simple parameter representation of yield behavior of niobium is feasible in terms of pertinent engineering variables.