TiAl Intermetallics

Abstract

Intermetallic titanium aluminides offer an attractive combination of low density and good oxidation and ignition resistance with unique mechanical properties. Thus, they are one of the few classes of emerging materials that have the potential to be used in demanding high‐temperature structural applications whenever specific strength and stiffness are of major concern. Advanced TiAl alloys have very complex microstructures with important features at the nanometer scale. There is an intimate correlation between the alloy chemistry, constitution, microstructure, and mechanical properties, which has to be considered in order to meet the desired properties. These concerns are addressed in this chapter through a global commentary on the physical metallurgy of TiAl‐based alloys. Particular emphasis is paid on recent developments of TiAl alloys with enhanced high‐temperature capability for application in aeroengines. Since TiAl alloys are now at the point of application, this chapter serves the materials' engineers as guidance in the huge body of literature concerning gamma titanium aluminide alloys going back nearly 20 years.