为了研究多组元复合添加对钨基合金晶粒组织稳定性的影响，本工作制备了晶粒组织均匀、平均晶粒尺寸相近的W-10Cr和W-5Cr-5Sc超细晶合金，研究了2种钨基合金晶粒组织的热稳定性。结果表明，2种钨基合金晶粒突发长大的温度约为1300 ℃，比纯W提高了约200 ℃。在热失稳温度下晶粒长大指数和晶粒长大激活能均达到最小值，2种钨基合金的晶粒长大指数远大于纯W热失稳的晶粒长大指数，当温度超过热失稳温度后，W-5Cr-5Sc合金的晶粒长大速率比W-10Cr合金更小。W-10Cr合金的高温稳定化机制归因于富Cr相的析出和Cr的晶界偏聚，W-5Cr-5Sc合金的高温稳定化机制为富Sc相的析出以及Cr、Sc在晶界的共偏聚作用。

W-based alloys play an indispensable role in various fields, such as aerospace and nuclear industries. However, their thermal stability decreases with grain structure refinement, limiting their high-temperature applications. Although certain solute elements can enhance thermal stability through phase separation or grain boundary segregation, a systematic research on the extent of grain structure stabilization and the mechanisms of multicomponent addition is lacking. Herein, ultrafine-grained W-10Cr and W-5Cr-5Sc alloys with uniform grain structures and similar average grain sizes were prepared. The thermal stabilities of these W-based alloys were systematically investigated to elucidate their stabilization mechanisms. Results indicate that sudden grain growth occurs at approximately 1300 ^oC in W-10Cr and W-5Cr-5Sc alloys, representing an increase of approximately 200 ^oC compared with pure W. Kinetic analysis shows that the grain growth index and activation energy for grain growth are minimized at temperatures corresponding to thermal destabilization. Moreover, the grain growth indices of W-10Cr and W-5Cr-5Sc alloys exceed those of pure W during thermal instability. Furthermore, beyond the thermal destabilization threshold, the grain growth rate of the W-5Cr-5Sc alloy was lower than that of the W-10Cr alloy. The addition of Sc modifies the Cr distribution in the alloy. In the W-10Cr alloy, the high-temperature stabilization mechanism of the grain structure was attributed to the precipitation of Cr-rich phases and the segregation of Cr at the grain boundaries. By contrast, the stabilization mechanism in the W-5Cr-5Sc alloy shifts toward the precipitation of Sc-rich phases along with the simultaneous segregation of Cr and Sc at the grain boundaries.