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本文应用蚀象法对电子束浮区区熔法制得的原生态钼单晶体中的亚晶界位错结构进行了直接观测。对于实验结果进行了细致的分析,并与亚晶界的Frank公式的一些预期结果比较,全面地证实了理论预测。对(111)面上平行蚀线方向的测量表明,它们大体沿着1/2〈111〉刃型位错的滑移面及攀移面的交线,从而证实了它们是这种位错所组成的一组位错倾侧型晶界。通过对蚀斑三叉亚晶界的分析,检验了推广后的Read-Shockley公式,同时表明存在着两组位错的倾侧晶界。对于(111)面上观察到的15组蚀线网络进行了分析,结果表明其中5组是1/2〈111〉/〈100〉网络,9组是〈100〉/〈110〉网络。分析中,除去应用Carrington等所发展的极图分析法以外,我们还根据Frank公式所规定的网线间距的关系式,提出了进一步定量检验的分析方法。实践证明,当极图分析不能获得唯一的结果时,这种定量检验法可以有效地确定位错网络的Burgers矢量。此外,我们还观察到奇位错和亚晶界交互作用的事例,特别是奇位错在亚晶界上引起“台阶”以及夹杂物和亚晶界交互作用的迹象。不同类型的亚晶界交接以及非平衡态的亚晶界也是经常可以观察到的。以上结果表明,蚀象法对于定量地研究原生态晶体中的亚晶界位错结构是极其有效的,其能力并不亚于电子显微镜薄膜透射法。Using etch-figure technique, we have directly observed dislocation structure of sub-boundaries in electron-beam zone-melted molybdenum single crystals. A thorough analysis of experimental results are given, these are further compared with the deductions derived from the Frank's formula for subboundaries, and the theoretical predictions are fully verified.The directions of parallel etch-lines observed on (111) plane are along the intersection lines of glide planes and climb plane, it proves that these are symmetrical tilt subboundaries composed of edge dislocations with Burgers vector 1/2. The verification of the generalized Read-Shockley formula for intersecting subboundaries revealed by etch-pitting (110) surface proves these to be asymmetrical tilt subboundaries composed of two sets of dislocations.15 sets of networks of etch-lines have been analyzed, in which 5 sets arc proved to be 1/2 / networks, 9 sets to be / networks. In the network analysis, in addition to the stereographic method used by Carrington ct al., we have developed a new method by verifying Frank's formula quantitatively and it proved to be effective in determining Burgers vectors of dislocation networks when the stereographic analysis failed to yield unique result.Besides, we have observed various patterns indicating interactions of singular dislocations with subboundaries, in particular, "steps" on the subboundaries induced by singular dislocations and also interactions of inclusions with subboundaries. Various types of subboundary junctions and non-equilibrium subboundaries have been observed and discussed.All these results prove that the etch-figure method of observing dislocations is an effective means for the quantitative study of dislocation substructure in crystals, comparable in power with that of transmission electron microscopy.
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