材料表面形成的晶界沟槽会影响表面物质的传输机制，引起晶界迁移的驱动力发生改变，从而影响晶粒长大动力学规律。本工作构建了耦合晶界沟槽演化和晶粒长大的相场模型，对晶界沟槽的形成过程进行了模拟。构建了多晶体系的自由能方程，总自由能的减少为体系的演化提供了驱动力；对迁移率系数进行了修正，使得晶界沟槽形成和晶粒生长遵循不同的动力学过程。然后，对UO₂陶瓷燃料晶界沟槽演化行为进行了模拟，结果表明，单个晶界的沟槽演化过程受表面扩散机制控制，且与Mullins经典理论解吻合较好。进一步研究表明，晶界沟槽的轮廓随着晶界的移动变得不再对称，而处于晶界移动方向前方的晶粒内出现更大的物质堆积。三维多晶薄膜结构的演化结果显示，所有晶粒朝着柱状晶结构演化，晶界与表面相交的位置逐渐产生了沟槽。此时，同一晶粒不同侧晶界所产生的沟槽会在晶粒表面发生重叠，晶界沟槽的轮廓形状也会发生改变。沟槽深度增加会使晶界移动速率减缓，晶粒长大过程变慢。

The grain boundary grooves formed on material surface significantly affect the mechanisms of mass transport, altering the driving force for grain boundary migration, and consequently influencing the kinetics of grain growth. Herein, a phase-field model is developed to simulate the coupled evolution of grain boundary grooving and grain growth in UO₂ ceramic fuels. The process of developing the model begins by constructing a free energy equation for a polycrystalline system, where the reduction in total free energy drives system evolution. The mobility coefficients are then adjusted to ensure that the formation of grain boundary grooves and grain growth follow different kinetic processes. Results show that groove evolution at individual grain boundary is controlled by surface diffusion, aligning closely with Mullins' classical theoretical solution. Moreover, with the movement of grain boundaries, the groove contours become decreasingly symmetric, with increased material accumulation occurring in the grain in front of the moving direction of the grain boundary. The evolution results of a 3D polycrystalline thin film structure show that all grains evolve toward a columnar crystal structure, with grooves gradually forming at the intersections of grain boundaries and the surface. Moreover, grooves generated by different grain boundaries within the same grain tend to overlap on the grain surface, altering the groove contours. With increasing groove depth, grain boundary movement becomes increasingly slow, ultimately reducing the rate of grain growth.