The influence of composition and processing on the structure and properties of TiAl-based alloys

Alloys based on TiAl, with Al contents between 44 and 48 at %, have been further alloyed and processed to produce a range of microstructures and the influence of these different compositions and structures on the mechanical properties have been assessed. In addition, the microstructural stabilities of some of these alloys, against exposure at likely operating temperatures, have been determined and any changes in microstructure correlated with changes in properties. The observations are discussed in terms of the factors which influence the strength of these alloys and in terms of the balance between obtaining alloys and structures which have the desired combination of properties, but also have acceptable stability at temperatures at which they are likely to be used. Finally, in the light of the current knowledge, some questions are addressed concerning the development of commercially successful TiAl-based alloys. (C) 1998 Elsevier Science Limited. All rights reserved.