Effect of tungsten and zirconium on structure and properties of niobium

Abstract

The individual and combined effects of W and Zr additions on macrostructure, microstructure and mechanical properties of Nb have been investigated. Nb, Nb-10 wt% W, Nb-2.5 wt% Zr and Nb-10 wt% W-2.5 wt% Zr alloy ingots were prepared by electron beam drip melting using high purity Nb, W and Zr rods. Additions of W and Zr resulted in significant improvement in hardness and room temperature tensile strength. It is seen that the effect of 10 wt% W addition is more than that of 2.5 wt% Zr addition in improving room temperature strength of Nb, although on 'per wt% addition' basis, Zr is a more effective strengthener than W. It is also observed that the cumulative effects of 10 wt% W and 2.5 wt% Zr on grain refinement and strengthening are more than their respective individual effects.