Thermo-physical properties of A Ti-44Al-8Nb-1B alloy in the solid and molten conditions

The commercial implementation of TiAl alloys is currently hampered by difficulties in melting and casting them. Computer modelling has much to offer for helping to understand and optimise the widely-used Induction Skull Melting and investment casting techniques, but its application is limited by the lack of information of the thermo-physical properties of TiAl alloys. Obtaining data in the molten condition is particularly difficult due to the high reactivity of these alloys, and special containment techniques are required. This paper briefly describes the methods used by a number of European institutes including the pulsed heating (or exploding wire) technique, differential scanning calorimetry, levitation drop calorimetry, levitation dilatometry, a laser flash technique and a miniature electro-thermomechanical test system. Results are presented for the properties of a Ti-44Al-8Nb-1B alloy in the solid and molten conditions, including the density, electrical resistivity, enthalpy and thermal diffusivity.