Recent Advances in Gamma Titanium Aluminide Alloys
ABSTRACTGamma titanium aluminide alloys of current interest are two-phase alloys consisting of γ-TiAl phase as the matrix and a α2-Ti3Al phase as the second phase. The properties of these alloys depend on alloy composition, processing, microstructure, and their combination. Two major microstructural constituents are gamma grains and lamellar grains, the latter of which contain alternate layers of gamma (γ) and alpha-2 (α2) thin plates. The relative amounts and distribution of these two constituents are the main factors controlling mechanical properties. This paper reviews our current understanding of the composition/microstructure/property relationships. An extended discussion will be made on the fundamental aspects of the formation of lamellar structure during cooling and the evolution of microstructure occurring during thermomechanical treatments.