Processing of gamma-based TiAl alloys by torsional deformation

Wrought TiAl products produced by conventional hot-working procedures, like forging and extrusion, suffer from structural and chemical inhomogeneities, which are major concerns with regard to the reliability of components. In an attempt to overcome these problems TiAl alloys were hot-worked by torsional deformation. By this method a much higher strain and mechanical work can be imparted, which trigger dynamic recrystallization. The metallurgical potential of this technique will be assessed on the basis of standard metallography and chemical analysis. Particular emphasis is placed on shear localization processes, which often lead to premature failure of the work piece.