Zr bearing gama-TiAl induction melted

Abstract

This paper describes the processing results of TiAl alloys melted under argon atmosphere by induction melting, using crucibles made of calcia and stabilized zirconia. Castings were allowed to solidify inside the crucible, in order to simulate the worst situation using this processing. Segregation profiles of residual elements and microhardness of different phases were evaluated, as well as its relation with the “alpha-case” extension. Two TiAl alloys, with 1 at. % zirconium and zirconium free, were produced and heat treated aiming to replace their as-cast structure by a quasi-lamellar one. The respective zirconium partition amongst microconstituents was evaluated, being demonstrated that zirconium concentrates in the g-phase and increases the volume fraction of this constituent, showing the g stabiliser role of zirconium.