Effect of cyclic heat treatment with hot deformation on the microstructure and structural orientation of TC17 titanium alloy lamellae

Abstract

The effects of cyclic heat treatment and hot deformation on the spheroidization and orientation of the TC17 titanium alloy were investigated using a light microscope (LM) and electron backscattered diffraction (EBSD). The experimental results indicate that in the two-phase temperature range of a simple, cycle heat treatment, the spheroidization of the lamellar microstructure of the TC17 titanium alloy is finite. After cyclic heat treatment and compression deformation, the Widmannstatten structure disappears, the spheroidized α lamellae is more obvious, but the uniformity of its orientation is not greatly improved. In addition, the recrystallization velocity, and the strength and toughness of the two phases in deformation lead to a difference in their orientation, and the recrystallization velocity of the α phase is faster than that of the β phase. In the deformation process, the anisotropy of the α phase is preferentially reduced. On the other hand, during the hot deformation process, the degree of deformation of the α phase is lower than that of the β phase, because the α phase is harder than the β phase. The strain is primarily concentrated on the softer β phase adjacent to α phase, which produces greater uniformity in α phase than in the β phase.

Keywords

• tc17 alloy
• thermal mechanical treatment
• lamellar structure
• spheroidization
• orientation