PROPERTIES AND MICROSTRUCTURE OF TIAL-BASED ALLOYS

A range of TiAl-based alloys has been plasma melted and subsequently e ither isothermally forged, extruded or atomised and HIPped. The micros tructure and properties of these alloys have been determined and some aspects of the relation between processing route, alloy composition an d properties will be discussed. It is clear that room temperature stre ngths between 1000 and 300 Mpa can be obtained for different compositi ons and processing routes, but room temperature elongation is generall y the least attractive of the properties with values of 2% being typic al of the best observed. The relation between room temperature strengt hs and creep response is not straightforward and some typical results will be reported. On the basis of these observations and earlier work on the influence of high temperature exposure on the structure of lame llar and duplex alloys, it is suggested that there may be significant advantages of using processing routes which generate a fine grained du plex structure. (C) 1997 Elsevier Science S.A.