Direct production of the Nb-10%W-1%Zr-0.1%C alloys from the constituent metal oxides by the combined carbothermal reduction-electron beam melting method

An investigation of the combined carbothermal reduction-electron beam melting method of preparing Nb-W-Zr alloys is reported. In this process alloying proceeds during the simultaneous reduction of mixtures of oxides of the constituent metals. Subsequent melting in an electron beam furnace reduces the carbon and oxygen contents to the appropriate level for a commercial grade alloy. Complete homogenization and excellent control of the residual interstitial element contents in the alloys are assured in this manufacturing process. Isothermal degassing experiments and mass spectrometric measurements of the Nb-W-Zr-C-O solid solutions show that the carbon and some of the oxygen are removed as CO and that the remainder of the oxygen is removed as volatile suboxides such as NbO, NbO2 and ZrO. (Auth.)