Deformation and Recrystallization Behaviour of the TiAl Phase Constituting the TiAl/Ti3Al Lamellar Structure of Ti-rich TiAl Compounds.

We have grown TiAl crystals of a nearly stoichiometric composition composed of a single lamellar grain as wel Ias those composed of two lamel lar grai ns a nd stud ied thei r deformation behaviou r at room temperature, The deformation behaviour of lamellar grains dependsstrongly on their lamellar orientation.Yield stress is high for uniaxial loading perpendicular or parallel to the lamellar boundaries (the hard mode of deformation).while it is low for uniaxial loading at an intermediate angle (the easy mode of deformation).The tensile elongation for the easy mode of deformation can be as large as 20"/* at room temperature.By utilizing such easy mode of deformation, TiAl can be rolled up to 50'/• reduction in thickness at room temperature.Microstructures resulted from annealing of cold-rolled TiAl have been found to depend on the amount of reduction in thickness.