ALUMINIUM LOOS IN THE PROCESS OF Ti-6Al-7Nb SMELTING

Abstract

In the paper, results of experimental smelting of the Ti-6Al-7Nb alloy in a vacuum induction furnace are presented. The experiments were performed at 5-1000 Pa and 1973-2023 K. For the analysed alloy, a significant impact of pressure on aluminium loss was observed. Pressure reduction in the device from 1000 Pa to 5 Pa was accompanied by Aluminium content decrease from the initial value of 5.5 % mass to a value even below 3.2 % mass. Moreover, aluminium elimination was enhanced when the smelting temperature increased. Additionally, values of a so-called evaporation coefficient (Ω) were determined. In terms of titanium and niobium, ΩAl/Ti and ΩAl/Nb values suggest that, thermodynamically, aluminium loss may result from its intense evaporation from the investigated alloy.