Deformation Behavior of Ti-43 mol% Aluminum in α Single Phase Region and Orientation Distribution of Lamellae after Cooling

Abstract

High temperature uniaxial compression tests in the alpha single phase region were carried out on the Ti 43 molAl intermetallic compound in order to obtain oriented lamellar microstructure. The compression deformation temperatures and strain rates were from 1573 to 1623 K and 1.0×10 -4 to 5.0×10 -3 s -1 , respectively. Fully lamellar microstructures were observed after uniaxial compression deformation in the a single phase region followed by cooling to room temperature. The lamellar colony diameter depended on strain rate and test temperature. The diameter varied between 860 mm and a 300 mm. Stress strain curves showed work softening and the size of lamellar colony diameter varied depending on peak stresses. This suggests the occurrence of dynamic recrystallization. Texture measurements after uniaxial compression deformation showed the development of fiber texture during dynamic recrystallization. It is seen that the maximum pole density existed in 35 degrees away from the compression plane. The texture sharpens with the decrease in strain rate.

Deformation behavior of TiAl intermetallic compounds and orientation control by reactive diffusion and high-temperature uniaxial compression deformation

“…This sensitivity indicates that the process of controlling the lamellar orientation is important for the practical application of compounds. One group of researchers reported that the alignment of lamellae could be effectively controlled by high-temperature deformation in an D singlephase state [6] followed by heat treatment for the formation of a lamellar microstructure and deformation in a lamellar state [7][8][9]. The essential idea in one of the two processes was successfully applied on a practical scale to the trial production of a turbine disk [10].…”