High-pressure nanocrystalline structure of a shock-compressed single crystal of iron
High-pressure nanocrystalline structure of a shock-compressed single crystal of iron
复制标题
DOI：
10.1103/physrevb.78.220101
复制
发表时间：
2008-12-01
影响因子：
3.7
通讯作者：
Wark, Justin S.
中科院分区：
文献类型：
--
作者：
Hawreliak, James A.;Kalantar, Daniel H.;Wark, Justin S.
我们讨论了在冲击压缩过程中用原位X射线衍射法进行的晶粒度测量。我们的实验已经明确地表明，沿[100]方向加载高于13 Gpa的单晶铁冲击将从环境α相(BCC)转变为高度有序的多晶epsilon相(HCP)。在这里，我们给出了一个详细的衍射峰的形状分析，用一个改进的Warren-AVerbach方法来量化冲击压缩高压铁的微观结构。通过这种方法确定了epsilon相的颗粒尺寸在2到15 nm之间，这与大规模分子动力学模拟的结果是合理的一致。我们得出结论：单晶铁在冲击波从α相转变为epsilon相时变为纳米晶。
We discuss the grain-size measurements made during shock compression using in situ x-ray diffraction. Our experiments have shown unambiguously that single-crystal iron shock loaded above 13 GPa along the [100] direction will transform from the ambient alpha phase (bcc) to a highly ordered polycrystalline epsilon phase (hcp). Here, we present a detailed shape analysis of the diffraction peaks using a modified Warren-Averbach method to quantify the microstructure of shock-compressed high-pressure iron. The epsilon phase was determined through this method to have grain sizes between 2 and 15 nm, in reasonable agreement with results from large-scale molecular-dynamics simulations. We conclude that single-crystal iron becomes nanocrystalline in shock transforming from alpha to epsilon phase.