Development of a turbulence-free casting technique for titanium aluminides

As part of the EC-funded IMPRESS project, a novel technique has been developed for casting titanium aluminides which combines clean melting under argon in an Induction Skull Melting furnace with tranquil tilt pouring into a pre-heated ceramic shell mould. This has enabled good quality castings to be produced which are free from the entrained bubble defects which are routinely found when turbulent mould filling processes such as gravity casting are used. Examples are given of the use of this technique to cast blades up to 40 cm long.