Anisotropy Behavior of Dislocation Nucleation from a Sharp Corner in Copper
Anisotropy Behavior of Dislocation Nucleation from a Sharp Corner in Copper
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DOI：
10.1299/jcst.5.54
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Yu Sun;S. Izumi;S. Hara;S. Sakai
中科院分区：
文献类型：
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作者：
Yu Sun;S. Izumi;S. Hara;S. Sakai
用反应路径分析的方法，研究了FCC中90°和30°部分位错从尖角形核的过程。水晶铜。结果揭示了位错形核的各向异性，结果表明，30°部分位错的应力激活能约为90°部分位错的两倍，且前者的最大非弹性位移也较大。此外，30°部分位错的鞍点构型类似于半椭圆，而90°部分位错的鞍点构型更类似于半圆，反映了Burgers矢量对不同Peierls势垒的影响。表面重构的进一步研究表明，虽然表面还原促进了30°部分位错的形核，但它仍然比90°部分位错更不利于能量。这些结果表明，较高的Peierls势垒是导致30°部分位错成核的激活能较大的原因。
By means of reaction pathway analysis, we have investigated the nucleation of 90° and 30° partial dislocation from a sharp corner in an f.c.c. crystal copper. The anisotropy aspects of dislocation nucleation revealed by the results have shown that the stress-dependent activation energy of 30° partial dislocation is approximately twice over the counterpart of 90° partial dislocation, and that the maximum inelastic displacement for the former is also higher. Moreover, the shape of the saddle-point configuration of 30° partial dislocation is similar to a half-ellipse whereas in the case of 90° partial dislocation it is more like a semi-circle, reflecting the different Peierls barriers influenced by the Burgers vectors. Further study of the surface reconstruction demonstrates that although the nucleation of 30° partial dislocation has been enhanced by surface reduction, it is still more energy-unfavorable than the 90° partial dislocation. These results suggest that the higher Peierls barrier is responsible for the larger activation energy of 30° partial dislocation nucleation.