Effect of Annealing Treatment on Recrystallization Behavior of Ti-2Al-2.5Zr Titanium Alloy Tubes

The microstructural evolution and mechanical properties of cold-rolled Ti-2Al-2.5Zr alloy tubes during isothermal recrystallization annealing at 650 ℃, 700 ℃ and 750 ℃ were investigated. Electron backscatter diffraction (EBSD), optical microscopy and tensile tests were employed to analyze the microstructural evolution and strain energy release behavior of the alloy under different annealing process. The results reveal that the recrystallization behavior of Ti-2Al-2.5Zr titanium alloy is jointly regulated by annealing temperature and holding time, with temperature playing a dominant role. The optimal annealing parameter is determined to be holding at 700 ℃ for 90 min. The recrystallization process presents distinct staged characteristics. In the first stage of annealing, 80% of the matrix undergoes rapid recrystallization, while the recrystallization proceeds very slowly in the second stage. The grains with the orientation of (0, 35°, 30°) exhibit resistance to recrystallization. The main texture components of the cold-rolled state are largely retained after recrystallization annealing, and the grain orientation tends to transform from <\!\!10\bar10\!\!>\!\!\|\mathrmAD to <\!\!1\,1\bar20\!\!>\!\!\|\mathrmAD during recrystallization. The above findings provide a theoretical basis for the optimization of annealing process schedules for Ti-2Al-2.5Zr titanium alloy tubes.