Abstract: The mechanical properties and microstructure of an Fe-base superalloy GH35A have been examined after aging at 650—750℃ for 100—10000 h.The tensile strength of the alloy changes no more with aging temperature and the time at room temperature,but the ductility and impact toughness at room temperature,as well as the stress-rupture life up to 700℃ de- crease slowly during aging up to 10000 h The initiation time to worsen its properties becomes shorter as the aging temperature rises.The variation of the mechanical properties of the alloy was found mainly depending on the formation,morphology,distribution and characteristic of the σ-phase precipitation.

Key words: superalloy, aging, mechanical property, σ-phase, γ-phase