Deformation mode dependence of an exothermic chemical reaction in Ti/Si multilayered nanofilms
Deformation mode dependence of an exothermic chemical reaction in Ti/Si multilayered nanofilms
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DOI：
10.1016/j.msea.2020.140021
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发表时间：
2020-10
期刊：
影响因子：
6.4
通讯作者：
H. Hirakata;T. Shiraishi;T. Shimada
中科院分区：
文献类型：
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作者：
H. Hirakata;T. Shiraishi;T. Shimada
通过机械加载来控制化学反应是一项有趣但具有挑战性的任务。在我们的研究中，我们研究了Ti/Si多层纳米薄膜中的形变模式与放热化学反应的关系。堆积方向上的压缩、剪切和压剪混合模式被认为是引起化学反应的基本变形模式。我们发展了对多层纳米薄膜施加剪切和压缩剪切载荷的原位透射电子显微镜方法。在剪切和压剪试验中，纳米膜界面都发生了局部剪切变形，并且在一个非常局部的区域产生了新的界面。电子显微镜纳米束电子衍射表明，在局部剪切带上形成了Ti5Si4和/或TiSi的晶体结构。在局部剪切带处形成新的界面是化学反应的基本机制。这与现有的由均匀压缩变形引起的化学反应机理非常不同，在现有的机理中，化学反应发生在广泛的区域内。这些结果使得通过改变机械加载模式来控制并在局部纳米尺度上产生所需的形态化学反应成为可能。
Controlling chemical reactions by mechanical loading is an interesting but challenging task. In our research, we investigated the dependence of deformation modes on an exothermic chemical reaction in Ti/Si multilayered nanofilms. Compression, shear, and compression-shear mixed modes in the stacking direction were evaluated as basic deformation modes that can cause chemical reactions. We developed in-situ TEM methods for applying shear and compression-shear loads for multilayer nanofilms. In both the shear and compression-shear tests, localized shear deformation across the nanofilm interface occurred and new interfaces were generated in a very localized region. TEM nanobeam electron diffraction revealed that a crystal structure of Ti5Si4and/or TiSi was generated in the local shear band. The formation of a new interface at the localized shear band was the basic mechanism for the chemical reaction. This was very different from the existing mechanism of a chemical reaction induced by uniform compressive deformation, where the chemical reaction occurred over a wide area. These results make it possible to control and generate a desired morphological chemical reaction on a localized nanoscale by varying the mechanical loading mode.