In- and ex-situ study of the deformation behavior of the βo(ωo) phase in a Ti4Al3Nb alloy during high-temperature compression

Abstract

In-situ synchrotron-based high energy X-ray diffraction (HEXRD) and ex-situ Gleeble tests were conducted to investigate the deformation behavior of the βo(ωo) phase in a Ti4Al3Nb alloy. In samples compressed at 600 and 800 °C, the brittle ωo phase deforms mostly elastically, resulting in the failure of the Ti4Al3Nb alloy by premature fracture. In a sample deformed at 900 °C, the ωo phase mostly transforms into the βo phase under uniaxial loading. Moreover, the ductility of a Ti4Al3Nb alloy is largely enhanced at this temperature. In a sample deformed at 1000 °C, dynamic recrystallization (DRX) of the βo phase extensively takes place. Direction 1 (D1) and Direction 2 (D2) deviating from the loading direction with an angle of 65° ± 5° and 15° ± 5° are selected to analyze the lattice strain evolution of (110)βo lattice planes. At the late stage of macro strain hardening, deformed<110>βo//D1 oriented grains bear a higher load due to the occurrence of DRX in<110>βo//D2 oriented grains. Subsequently, DRX continues in<110>βo//D1 oriented βo grains. The coordinated deformation of βo grains ensures the good deformability of a Ti4Al3Nb alloy at 1000 °C.