The Effect of Heat Treatment on the Evolution of Microstructure and Texture in Ti80 Hot Rolled Pipe

Abstract

In this study, the microstructure and texture evolution of hot rolled Ti80 pipe annealing at 960°C and 990°C in α+β two-phase field have been investigated. The results showed that the dissolution of α phases induced the increase of texture components of primary α phases (α_P) and the α_P were the main factors that determine the final texture at 960°C. At 960°C, the microtextures of secondary α phases (α_S) were very close to that of α_P. As the annealing temperature increased to 990 °C, the main factors affecting the microtextures of α_S changed from the α_P to the recrystallized β grains. The textures of β phases were greatly influenced by the annealing temperature. The β phases at high temperature were not mainly from the grow up of residual β phases. It was formed by the transformation of α phases at room temperature. Consequently, this study could provide some ideas for decreasing the texture intensities of hot rolled Ti80 pipes, such as reducing the area of α colonies before rolling, scattering the crystal orientations of α_P, and controlling the size of recrystallized β grains.

Keywords
Titanium alloys; Texture; Heat treatment; Electron backscattered diffraction (EBSD)