Abstract:The influence of trace Zr element addition on the microstructure, room temperature and high-temperature mechanical properties of K492M superalloy was studied. The Zr content in the experimental alloys ranged from 60 ppm to 580 ppm. The results indicate that the addition of Zr element did not change the main phase constitution of the as-cast and heat-treated K492M alloys. The microstructure of the as-cast K492M alloy mainly consists of γ matrix phase, γ" precipitated phase, MC carbides and (γ+γ") eutectic phase. After heat treatment, the (γ+γ") eutectic phase is nearly eliminated, accompanied by the precipitation of M??C? carbides. The addition of Zr element significantly refines the grain structure of the as-cast and heat-treated K492M alloys. When the Zr content is 160 ppm, the grain structures of both the as-cast and heat-treated alloys exhibit the greatest refinement. With the increase of Zr content from 60 ppm to 580 ppm, the MC carbides in both the as-cast and heat-treated alloys tend to be refined, while Zr element addition has a minor effect on the volume fraction and size of γ" phase. The variation of Zr content has little effect on the tensile properties at room temperature and the tensile strength at high temperature (760 ℃) of the heat-treated alloys, but significantly influences the ductility at 760 ℃ and stress rupture life at 760 ℃/662 MPa. The alloy with 160 ppm Zr demonstrated the highest high-temperature elongation and the stress rupture life, which were 53.8% and 16.8% higher, respectively, compared to the alloy containing 0 ppm Zr.