Gamma titanium aluminide, TNB

A range of mechanical properties for wrought TNB alloy (Ti-45Al-8Nb-0.2C%) and cast Ti4522XD(Ti-45Al-2Nb-2Mn-XD) have been assessed. The influence of notch sensitivity on fatigue strength has been evaluated and compared in terms of different microstructure and alloy composition. The effects of complex loading on fatigue strength have also been investigated with pre-creep deformations of 0.5, 3 and 5%, pre-exposure to 700 °C for 24 and 150 h or pre-low cycle fatigue testing at 700 °C. The tolerance of these materials to foreign object damage (FOD) has also been compared with the nickel alloy IN718. Under most conditions the TNB alloy has shown superior performance to Ti4522XD and its FOD tolerance appears to be better than IN718.