Control of Lamellar Arrangement in TiAl Alloys by High-Temperature Deformation in α Single Phase and Subsequent Annealing in Two Phase Region

Abstract

A method to control the lamellar arrangement in TiAl intermetallic compounds is proposed. It consists of the high-temperature deformation in the α region to construct a texture and the subsequent annealing in the two phase region to precipitate the γ phase in a lamellar form. The method was examined by experiments on Ti-41 mol%Al. The high-temperature deformation resulted in the formation of a fiber texture in the α₂ phase. No significant change was observed in the texture of the α₂ phase after the precipitation treatment of the γ phase. Formation of a fiber texture was found in the γ phase consisting lamellae. Crystallographic analysis revealed that the pole density distribution of the γ phase can be understood by the so called Blackburn’s relationship between the α₂ and γ phases. It was concluded that the texture control at the high temperature α phase is effective to obtain the oriented arrangement of lamellae.