Review of alloy and process development of TiAl alloys

The improved understanding of the factors that control microstructure and properties of TiAl alloys is reviewed together with current work aimed at developing both wrought and cast products. It is suggested that the choice of alloy composition is perhaps far simpler than the complex literature would suggest and the factors that underlie alloy choice will be explained. These factors include the processability of the alloy as well as the properties and examples will be given where this dual approach of defining both processability and properties is central to the successful application. In addition other aspects of processing that will be discussed include cost-effective processing, accuracy of compositional control and control of processing conditions appropriate for the specific alloy. Some current applications of TiAl components are summarised before considering some of the challenges still remaining for TiAl-based alloys.