Influence of the Slag Composition on the Fluorine Absorption in γ‐TiAl During Iesr

Abstract

Because of the oxidation resistance of -TiAl-alloys the long term use is limited to temperatures up to 700 °C. In literature, it has been reported that the so called halogen effect has an outstanding improvement on the oxidation resistance of -TiAl. This implication is based on the forming of gaseous Al-halides which are oxidized to Al 2 O 3 on the surface resulting in a protective alumina scale.To investigate the absorption of fluorine in -TiAl during electroslag remelting and to enhance the oxidation resistance of the produced alloy by bulk-fluidization a series of tests was performed at IME. Hence, in a 400 kW lab scale furnace multiple electrodes of Ti-45Al were remelted by using a CaF 2 flux. The slag composition was varied by partially substitution of CaF 2 with MgF 2 . The alloys as well as the slag were analyzed on their composition to set up the fluorine content by influencing the melting parameters.