Study on High Temperature Tensile Properties and Microstructure of a Tial-Based Alloys

The high temperature tensile test of a Ti-45Al-5Nb alloy was carried out at deformation temperatures of 880 °C and 1000 °C, with strain rates of 0.001 s⁻¹ and 0.0125 s⁻¹, respectively. Scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD) were used to analyse the microstructure of different tensile parts. The results showed that under the deformation conditions of 880 °C / 0.001 s⁻¹ and 880 °C / 0.0125 s⁻¹, the alloy underwent brittle fracture, and microstructure was basically unchanged, compared with the original one. Deformed at 1000 °C/0.001s⁻¹, the alloy exhibited plastic deformation and mixed brittle and plastic fracture. Dynamic recrystallization was the main softening mechanism, and the γ phase and B2 phase contents increased by 6.7% and 190.2%, respectively, compared with that deformed at 880 °C/0.0125s⁻¹. (paper)