Itoh K, Yamada R, Saida J, Ikeda K, Otomo T
Graduate School of Education, Okayama University, 3-1-1 Tsushima-Naka, kita-ku, Okayama 700-8530, Japan.
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
J Phys Condens Matter. 2021 May 28;33(27). doi: 10.1088/1361-648X/abfc12.
The structure of CuZramorphous alloy was investigated in terms of packing density and free volume by using neutron, x-ray diffraction and reverse Monte Carlo (RMC) modelling. The RMC model was analysed by a method of decomposing the three-dimensional atomic configuration into fundamental polyhedral units (termed as 'holes' referencing the Bernal's works) of which faces are all triangles consisting of chemical bonds. Not only tetrahedral and octahedral holes but also other larger holes were identified. Moreover, the atomic packing fractions and free volumes in the respective polyhedral holes were evaluated with reference to those for the corresponding crystal structures. The results show that the distribution of free volumes for the larger holes can be described by the exponential function assuming that there are no energetic interactions between each other. On the other hand, the local structural fluctuations due to densely and loosely packed tetrahedral holes were observed, leading to the negative free volume spaces.
通过中子、X射线衍射和反向蒙特卡罗（RMC）建模，从堆积密度和自由体积的角度研究了CuZr非晶合金的结构。通过将三维原子构型分解为基本多面体单元（参照伯纳尔的著作称为“孔”）的方法对RMC模型进行了分析，这些单元的面均为由化学键组成的三角形。不仅识别出了四面体和八面体孔，还发现了其他更大的孔。此外，参照相应晶体结构的原子堆积分数和自由体积，对各个多面体孔中的原子堆积分数和自由体积进行了评估。结果表明，假设较大孔之间不存在能量相互作用，则其自由体积分布可用指数函数描述。另一方面，观察到由于紧密和松散堆积的四面体孔导致的局部结构波动，从而产生了负自由体积空间。
