Observation of atomic diffusion at twin-modified grain boundaries in copper
Observation of atomic diffusion at twin-modified grain boundaries in copper
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DOI：
10.1126/science.1160777
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发表时间：
2008-08-22
期刊：
影响因子：
56.9
通讯作者：
Tu, K. N.
中科院分区：
文献类型：
--
作者：
Chen, Kuan-Chia;Wu, Wen-Wei;Tu, K. N.
晶界影响原子和电子在多晶固体中的迁移，从而影响许多机械和电学性能。通过在铜颗粒中引入纳米级孪晶缺陷，我们发现可以改变晶界结构和原子沿晶界的扩散行为。利用原位超高真空和高分辨电子显微镜，观察到了孪晶晶界中电迁移诱导的原子扩散。发现孪晶界与晶界相交处的三相点使晶界和表面电迁移减慢一个数量级。我们认为这是由于在三重点处新的一步成核的孕育时间造成的。较长的孵化时间减慢了原子传输的整体速度。
Grain boundaries affect the migration of atoms and electrons in polycrystalline solids, thus influencing many of the mechanical and electrical properties. By introducing nanometer- scale twin defects into copper grains, we show that we can change the grain- boundary structure and atomic- diffusion behavior along the boundary. Using in situ ultrahigh- vacuum and high- resolution transmission electron microscopy, we observed electromigration- induced atomic diffusion in the twin- modified grain boundaries. The triple point where a twin boundary meets a grain boundary was found to slow down grain- boundary and surface electromigration by one order of magnitude. We propose that this occurs because of the incubation time of nucleation of a new step at the triple points. The long incubation time slows down the overall rate of atomic transport.