Phase Transformations and Recrystallization Processes during Synthesis, Processing and Service of TiAl Alloys

Abstract

Titanium aluminides alloys based on the intermetallic phases 2(Ti3Al) and (TiAl) are one of the few classes of emerging materials that have the potential for innovative applications in advanced energy conversion systems whenever low density, good high-temperature strength and resistance against ignition and corrosion are of major concern. The outstanding thermo-physical properties of the individual phases mainly result from the highly ordered nature and directional bonding of the compounds. However, two-phase 2(Ti3Al)+(TiAl) alloys exhibit a much better mechanical performance than their monolithic constituents (TiAl) and 2(Ti3Al), provided that the phase distribution and grain size are suitably controlled. The synergistic effects of the two phases are undoubtedly associated with the many influences that the microstructure has on deformation and fracture processes.