Alloying Effects of Tungsten and Molybdenum on the Compressive Deformation Properties of Niobium

Abstract

  The alloying effects of tungsten (W) and molybdenum (Mo) on the mechanical properties of niobium (Nb) have been investigated by means of Vickers hardness test and cold upsetting test. It is found that the alloying effects of W and Mo on the Vickers hardness for the as-cast samples are nearly the same and the hardness increase almost linearly with increasing the total amount of alloying elements, W and Mo. The compressive yield stress of the binary and ternary alloys also increase almost linearly with increasing the amount of the alloying elements into Nb. On the other hand, the alloying effects of W and Mo on the work hardening behavior of the alloys appear to be different. For example, the flow stress of Nb-5 mol%W alloy is higher than that of Nb-5 mol%Mo alloy after yielding in the upsetting test. In fact, the work hardening exponent, n, in the power low is larger for Nb-5 mol%W alloy than Nb-5 mol%Mo alloy.