To date, much research has been conducted into the effect of migration pinning on the grain size in polycrystalline materials. However, effects of migration pinning on the grain-boundary structure and its transition have not been illuminated. Here, using transmission electron microscopy (TEM) we have explored the pinning effects for the grain boundary in a Ni bicrystal. During TEM specimen preparation, a hole was intentionally drilled in the middle of the grain boundary as a pinning point against grain-boundary migration. The specimen was heated to 600 °C. The grain boundary is driven to migrate by both the surface energy anisotropy and the total strain energy reduction. Grain-boundary facets with a plane orientation of {0 3 2}//{1 1 1} appear near the hole. The facets undergo a structural transition from atomically flat to rough with increasing distance from the hole. A pinning force exerted by the hole suppresses the migration of the grain boundary near the hole, indicating that the grain-boundary region away from the hole is subjected to a higher driving force. It certainly appears that the phenomenon originates from a change in driving force with the distance from the hole, being a signature of kinetic roughening.

中文翻译：

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镍晶粒边界的迁移钉扎和粗糙化转变

迄今为止，已经进行了许多研究来研究迁移钉扎对多晶材料中晶粒尺寸的影响。然而，尚未阐明迁移钉扎对晶粒边界结构及其过渡的影响。在这里，我们使用透射电子显微镜（TEM）探索了镍双晶中晶界的钉扎效应。在TEM样品制备过程中，有意在晶界中间钻了一个孔，作为防止晶界迁移的固定点。将样品加热到600℃。表面能的各向异性和总应变能的降低都促使晶界迁移。平面方向为{0 3 2} // {1 1 1}的晶界面出现在孔附近。随着距孔的距离增加，这些小面经历了从原子平面到粗糙的结构过渡。孔施加的钉扎力抑制了孔附近的晶界的迁移，这表明远离孔的晶界区域受到较高的驱动力。显然，该现象似乎是由于驱动力随距孔的距离而变化而引起的，这是动力学粗糙化的标志。