Institut für Materialphysik, Westfälische Wilhelms Universität Münster, Wilhelm Klemm Straße 10, D-48149, Münster, Germany.
Nano Lett. 2012 Jul 11;12(7):3448-54. doi: 10.1021/nl300751q. Epub 2012 Jun 6.
Triple junctions (TJ), singular topological defects of the grain boundary (GB) structure, get a dominant role for grain growth and atomic transport in nanocrystalline matter. Here, we present detailed measurements by atom probe tomography, even of the temperature dependence of TJ transport of Ni in nanocrystalline Cu in the chemical regime of interdiffusion. An unexpected variation of the effective width of merging GBs with temperature is detected. It is demonstrated that proper measurement of TJ transport requires taking into account this remarkable effect. TJ diffusion is found to be a factor of about 200 faster than GB diffusion. Its activation energy amounts to only two-thirds of that of the GB.
三叉点（TJ）是晶界（GB）结构的单一拓扑缺陷，在纳米晶体物质的晶粒生长和原子输运中起着主导作用。在这里，我们通过原子探针层析术进行了详细的测量，甚至包括在互扩散化学体系中 Ni 在纳米晶 Cu 中的 TJ 输运的温度依赖性。检测到合并晶界的有效宽度随温度的意外变化。结果表明，TJ 输运的正确测量需要考虑到这一显著影响。TJ 扩散的速度比晶界扩散快约 200 倍。其激活能仅为晶界的三分之二。
