Dislocations in Polyethylene Single Crystals
Dislocations in Polyethylene Single Crystals
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聚乙烯单晶中的位错
DOI：
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发表时间：
1964
期刊：
影响因子：
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通讯作者：
V. F. Holland
中科院分区：
文献类型：
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作者：
V. F. Holland
利用叠层产生的莫尔条纹，在聚乙烯单晶中观察到位错，并对其进行了表征。通过暗场和明场电子显微镜对位错的分析表明，它们是部分（不完全）位错。这些偏导数涉及终止{110}面，并具有1/2 a，1/2 B，γc θ的Burgers矢量。大多数位错涉及{110}面，包含链褶皱。位错的发生作为孤立的部分，而不是成对的意味着低堆垛层错能的聚乙烯晶格。当我们考虑到"断层“主要是由从正常位置简单旋转的链组成时，这个结论并不奇怪。单晶的退火使位错密度增加了大约一千倍，此外，在暗场中还产生了平行于晶体长对角线的带。这些谱带主要出现在晶体边缘。被选中的是…
Dislocations have been observed and characterized in polyethylene single crystals by means of moire patterns produced by superimposed lamellas. Analysis of the dislocations by dark and bright field electron microscopy has revealed that they are partial (imperfect) dislocations. The partials were shown to involve terminating {110} planes and to have Burgers vectors of 〈½a, ½b, γc〉. Most of the dislocations involved {110} planes containing chain folds. The occurrence of the dislocations as isolated partials rather than paired ones implies a low stacking fault energy for the polyethylene lattice. This conclusion is not surprising when one considers that the ``faults' consist mostly of chains which simply have been rotated from their normal positions.Annealing of single crystals increased approximately one‐thousand fold the dislocation density, and in addition produced, in dark field, bands parallel to the long diagonals of the crystals. These bands were found predominantly at the crystal edges. Selected are...