Pressure-induced phase transition in icosahedral Al-Li-Cu quasicrystals
Pressure-induced phase transition in icosahedral Al-Li-Cu quasicrystals
复制标题
二十面体 Al-Li-Cu 准晶中压力诱导的相变
DOI：
10.1080/01418619608243532
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发表时间：
1996
影响因子：
1.6
通讯作者：
S. Lefébvre
中科院分区：
文献类型：
--
作者：
A. Sadoc;J. Itié;A. Polian;S. Lefébvre
摘要我们报道了在准流体静力学条件下，在高压下，对二十面体Al6Li3Cu准晶进行了原位扩展X射线吸收精细结构（EXAFS）研究。EXAFS实验在Cu K吸收边进行，从常压到33GPa，给出了铜原子第一近邻平均距离随压力的变化。这个平均距离随着压力的增加而单调减小，直到12 GPa，直到20 GPa几乎保持不变，然后增加。这种原子间距离的增加被解释为相变的指纹。通过Murnaghan状态方程拟合了相对第一近邻距离，直到12 GPa，使得对于一阶导数B′0 = 6，零压体积模量为B 0 = 71 GPa。在铜原子周围发现的该B 0局部值接近纯铝的整体体积模量。释放压力后，Al6Li3Cu准晶表现出明显的非晶化。
Abstract We report in-situ extended X-ray absorption fine-structure (EXAFS) studies of icosahedral Al6Li3Cu quasicrystals, without any aluminium excess, under a high pressure in quasihydrostatic conditions. The EXAFS experiments have been performed at the Cu K absorption edge from ambient pressure up to 33 GPa and give the variation in the average distance of fist neighbours around copper atoms against pressure. This average distance decreases monotonically with increasing pressure up to 12 GPa, remains almost constant up to 20 GPa and then increases. This increase in the interatomic distance is interpreted as the fingerprint of a phase transition. The relative first-neighbour distance has been fitted, up to 12 GPa, by a Murnaghan equation of state so that the zero-pressure bulk modulus is B 0 = 71 GPa for a first derivative B′0 = 6. This B 0 local value found around copper atoms is close to the overall bulk modulus of pure aluminium. After release of the pressure, the Al6Li3Cu quasicrystal shows spectacu...