Texture evolution during Isothermal compression process of Ti-22Al-25Nb alloy in B2 phase region

^a State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an, 710072, China
² Defense Technoloies Innovation Center of precision forging and ring rolling, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an, 710072, China

Abstract

In the present work, the hot deformation behavior, dynamic recovery, dynamic recrystallization and texture evolution of Ti-22Al-25Nb alloy on the conditions of 1100°C with four different thickness reductions (35%, 50%, 65% and 80%) are investigated by isothermal compression testing on Gleeble-3500 thermo-mechanical simulator. The strain rate is 0.1mm/s^-1. Subsequently, metallographic observation and EBSD analysis are carried out. The results show that during the hot deformation, the dynamic recovery (DRV) and dynamic recrystallization (DRX) strongly affect the microstructure and texture evolution. It is observed that with the strain increasing, the intensity of η_bcc-fiber increases firstly (crystallographic fiber axis <100> parallel to the compression direction). When the thickness reduction reaches to 80%, the intensity of <001> pole becomes stronger expectedly. Whereas the η_bcc-fiber transform into cube components ({100} <001>) unexpectedly. In addition, as the strain increases through 35%-80%, the fraction of large misorientation grain boundaries and fraction of DRX grains gradually increase due to continuous recrystallization. The evolution mechanism of grain orientations and texture during the DRX process will be discussed.