The discovery of ordered γ 0 precipitates in the system of Co-Al-W-based alloys paves a new pathway for the development of hightemperature superalloys applied at high temperatures. [1,2] Compared to the widely used Ni-based superalloys, the potential for higher temperature capability is expected with Co-based superalloys due to the higher melting temperature of the major matrix component, Co. [3,4] This is very attractive for hot-end components in advanced aeroengines to further improve the fuel efficiency and mechanical properties. In addition, Co-based superalloys usually have a higher sulfide melting temperature than Ni-based superalloys, which is beneficial for the long-term service in an environment containing sulfur, such as industrial gas turbines. [4] However, due to the complexity of the actual service environment, commercial superalloys need to fulfill a variety of physical and chemical properties simultaneously, such as creep, fatigue, oxidation, corrosion, and density, which is done by tailoring the alloy composition typically comprising more than nine components. [5] Until now, the research of γ 0 -strengthened Co-based superalloys has gradually evolved from exploring alloying principles, considering individual or multiple elements, [6][7][8] to the optimization of different properties in an alloy with complex components (≥7). [9][10][11] Many researchers have demonstrated that Ni addition can significantly expand the γ þ γ 0 phase region, [12,13] which contributes to the tailoring of the microstructure by the addition of other refractory elements. Thus, a series of CoNi-based superalloys have been developed in recent years. Ta, Ti, and Nb improve the γ 0 solvus temperature (T γ 0 ) and the temperature capability, [14][15][16] while they also promote the precipitation of TCP phases, which are harmful to mechanical properties. [17,18] Cr is beneficial for improving the oxidation and corrosion resistance, but it reduces the T γ 0 and area fraction of γ 0 precipitates (A γ 0 ). [19,20] Mo, W, and Re provide good solid solution strengthening effects in Ni-based superalloys with a negative misfit (a γ 0 < a γ ). In contrast, Mo lowers the misfit of γ 0 -strengthened Co-based superalloys, which generally exhibit a positive misfit (a γ 0 > a γ ), by increasing the lattice constant of the γ matrix. This normally results in a transition of the γ 0 precipitate morphology from cuboidal to spherical, [21] which is beneficial for the microstructural stability during the long-term service process. W is the γ 0 -forming element in γ 0 -strengthened Co-based superalloys, [22] and its solution effect is lower than that in Ni-based superalloys. Moreover, the addition of W will greatly increase the density. Although Re can significantly improve the creep resistance of Ni-based superalloys by strongly