Strain mapping of a triple junction in nanocrystalline Pd
Strain mapping of a triple junction in nanocrystalline Pd
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DOI：
10.1016/j.actamat.2011.08.020
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发表时间：
2011-11
期刊：
影响因子：
9.4
通讯作者：
H. Rösner;C. Kübel;Y. Ivanisenko;L. Kurmanaeva;S. Divinski;M. Peterlechner;G. Wilde
中科院分区：
文献类型：
--
作者：
H. Rösner;C. Kübel;Y. Ivanisenko;L. Kurmanaeva;S. Divinski;M. Peterlechner;G. Wilde
像差校正透射电子显微镜被用来提供在纳米晶Pd的三重结的结构信息。这种三重结由两个相交的具有一个999晶界的993孪晶界组成，并通过999晶界连接到一个四重点。一个全面的应变分析，这三重结几何相位分析，并与分子动力学模拟。主要结果如下：（i）三重结核心的应变场具有位错特征，延伸距离约为0.5nm，（ii）相交边界导致a_（02）的净平移，对应于面心立方晶格中a_（02）位错的Burgers矢量;（iii）从三重结沿着晶界出现的向错被从四重点出现的符号相反的向错平衡。根据观察，三重结的核心可以用位错的应变场来描述，用12 Gb 2估算其能量约为1.7×10− 9 Jm −1。向错偶极子的存在被认为是必不可少的稳定观察到的结构。
Aberration-corrected transmission electron microscopy was used to provide structural information on a triple junction in nanocrystalline Pd. This triple junction consists of two intersecting Σ3 twin boundaries with a Σ9 grain boundary and is connected to a quadruple point via the Σ9 grain boundary. A comprehensive strain analysis of this triple junction using geometric phase analysis is presented and compared with a molecular dynamics simulation. The main results are: (i) the strain field of the core of the triple junction shows dislocation character and extends over a distance of about 0.5nm; (ii) the intersecting boundaries result in a net translation of a02, which corresponds to a Burgers vector of an a02〈110〉 dislocation in the fcc lattice; (iii) a disclination emerging from the triple junction along the Σ9 grain boundary is balanced by a disclination of opposite sign emerging from the quadruple point. Based on the observation that the core of the triple junction can be described by the strain field of a dislocation, its energy was estimated using 12Gb2to be about 1.7×10−9Jm−1. The presence of a disclination dipole is thought to be essential for stabilization of the structure observed.