<p>TiAl-based alloys offer excellent specific strength and oxidation resistance, but poor creep resistance limits their use in aeroengine hot sections. To mitigate this shortcoming, the present work utilizes powder metallurgy technique for fabrication of Ti-45Al-5Nb (at.%) and a subsequent systematic investigation of microstructural attributes relating to high-temperature creep behavior. The microstructure of the Nb-containing TiAl-based alloys is predominantly <i>γ</i>-TiAl and <i>α</i>₂-Ti₃Al duplex microstructure. According to creep data, the stress exponent <i>n</i> value and creep activation energy <i>Q</i>_c value of Ti-45Al-5Nb alloys in the test range are 4.1 and 870.4&#xa0;kJ/mol, confirming that the creep deformation mechanism of the alloy is mainly dislocation climb behavior. Nb enhances the high-temperature strength and creep resistance of the alloy through solid solution strengthening. Finally, during the creep process, stress concentration areas appear at the interface of the matrix, leading to the initiation of cavities and the propagation of cracks.</p> Graphical abstract <p></p>