Room-temperature plastic deformation modes of cubic ZnS crystals
Room-temperature plastic deformation modes of cubic ZnS crystals
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DOI：
10.1016/j.actamat.2023.118738
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发表时间：
2023-02
期刊：
影响因子：
9.4
通讯作者：
Shunsuke Kitou;Y. Oshima;A. Nakamura;K. Matsunaga;H. Sawa
中科院分区：
文献类型：
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作者：
Shunsuke Kitou;Y. Oshima;A. Nakamura;K. Matsunaga;H. Sawa
光环境极大地改变了硫化锌（ZnS）单晶的可塑性：它们在黑暗中表现出延展性，而在光照下表现出脆性。利用同步辐射X射线衍射（XRD）、透射电镜（TEM）和扫描电镜（STEM）等测试手段，研究了它们的光环境塑性变形模式。XRD分析揭示，ZnS晶体最初具有两个体积分数几乎相同的畴，具有孪晶关系，并在黑暗中发生塑性变形，伴随着畴体积比的变化（即孪晶的消失）。还观察到，在超过10%的塑性应变时，畴体积比变得恒定为0.2。的STEM分析表明，在黑暗中的变形模式开关在约10%的塑性应变从滑移变形的滑动孤立的部分位错的同时滑动的主要领域内的配对的部分。虽然ZnS单晶表现出只有百分之几的塑性应变在灯光下，孤立的局部和由此产生的域体积比的变化类似于在黑暗中的局部滑移得到了证实。也就是说，在初始阶段的ZnS的变形模式是相似的，无论光环境，虽然宏观变形行为有很大的不同。
Light environment drastically alters the plasticity of zinc sulfide (ZnS) single crystals: they exhibit ductility in darkness while brittleness in lights. This study investigated their microscopic deformation modes of the light-environment-dependent plasticity, by using synchrotron X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning TEM (STEM) measurements. The XRD analyses disclosed that the ZnS crystals originally have two domains with almost the same volume fraction with a twin relationship and plastically deform in darkness, accompanying changes in the domain volume ratio (namely extinction of twins). It was also observed that the domain volume ratios become constant to be 0.2 at more than 10% plastic strains. The STEM analyses indicated that the deformation mode in darkness switches at around 10% plastic strain from slip deformation by glide of isolated partial dislocations to by simultaneous glide of paired partials inside the major domains. Although ZnS single crystals exhibited only a few percent of plastic strains in lights, localized glide of isolated partials and the resultant changes in domain volume ratios similar to in darkness were confirmed. That is, the deformation modes of ZnS at the initial stage were similar regardless of light environments although the macroscopic deformation behaviors were quite different.