Coarse grains are formed during thermomechanical processing for the widely studied NiCoCr medium-entropy alloy (MEA) due to the lack of effective approaches to restrain grain growth. Here, a novel integrated method combing solute drag and Zenner pinning effects are proposed. The 0.5 at.% C was added to precipitate carbides which generates pinning of the grain boundaries; while solute drag is implemented by 3 at.% addition of Mo with low self-diffusion coefficient. Results show that most of Mo is dissolved in the matrix and M₂₃C₆ carbides uniformly precipitated after aging. The combined method shows a significant effect on controlling grain growth and results in much finer equiaxed grains. A very high growth activation energy of 511 $\text{kJ}/\text{mol}$ was obtained, double that of NiCoCr MEA (251 $\text{kJ}/\text{mol}$). This work shows that the grain growth kinetics of the NiCoCr based MEA during traditional thermomechanical processing can be tuned by adjusting carbide precipitates and selecting appropriate solute elements.

由于缺乏抑制晶粒生长的有效方法，广泛研究的 NiCoCr 中熵合金 (MEA) 在热机械加工过程中会形成粗晶粒。在这里，提出了一种结合溶质阻力和 Zenner 钉扎效应的新型集成方法。添加 0.5 at.% C 以沉淀碳化物，从而导致晶界钉扎；而溶质阻力则是通过添加 3 at.% 的低自扩散系数的 Mo 来实现的。结果表明，时效后大部分Mo溶解在基体中，M ₂₃ C ₆碳化物均匀析出。组合方法显示出对控制晶粒生长的显着效果，并产生更细的等轴晶粒。511 的非常高的生长活化能$\text{千焦}/\text{摩尔}$ 获得了两倍于 NiCoCr MEA (251 $\text{千焦}/\text{摩尔}$）。这项工作表明，在传统热机械加工过程中，NiCoCr 基 MEA 的晶粒生长动力学可以通过调整碳化物沉淀和选择合适的溶质元素来调节。