Development of a Nb-free TiAl-based intermetallics with a low-temperature superplasticity

In this work, the possibility for developing TiAl-based intermetallics without Nb element was explored. Fe and Mo were alloyed with TiAl intermetallics. By using Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), electron back scattered diffraction (EBSD) and mechanical tests, the microstructural evolution and deform behavior of a Ti-45Al-3Fe-2Mo intermetallics were investigated. The results indicate that the TiAl-Fe-Mo intermetallics show a (B2 + α2 + γ) three-phase microstructures. The microstructures are significantly refined to about 14 μm by additions of Fe and Mo. The TiAl-based intermetallics show a high ductility at 750 °C and a superplastic behavior at 790 °C. The dynamic recrystallization of β(B2) grains is the main acting mechanism for the superplastic behavior of TiAl-based intermetallics at low-temperatures.