Sedimentation process for atoms in a Bi-Sb system alloy under a strong gravitational field: A new type of diffusion of substitutional solutes
Sedimentation process for atoms in a Bi-Sb system alloy under a strong gravitational field: A new type of diffusion of substitutional solutes
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Bi-Sb系合金中原子在强引力场下的沉降过程：一种新型的替代性溶质扩散
DOI：
10.1080/01418610208239619
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
T. Mashimo
中科院分区：
文献类型：
--
作者：
M. Ono;T. Mashimo
摘要根据Mashimo等人的研究，在最大加速度大于106 g的强引力场下，取代溶质原子在70 mol ~ bi ~ 30 mol ~ Sb合金中沉积，形成了原子尺度的梯度结构。本研究采用自洽理论对Bi-Sb合金中的沉积过程进行了模拟，探讨了扩散机理。首先在无限半径范围内进行了仿真，验证了仿真程序的有效性。通过改变沉积扩散系数与内部化学势的比值，模拟有限半径范围内的沉积过程，与实验结果进行比较。模拟结果表明，即使溶质替代在该体系中起作用，沉淀扩散系数仍比常规扩散系数大。这表明沉积的扩散机制不同于空位机制。
Abstract An atomic-scale graded structure had been formed by the sedimentation of substitutional solute atoms in a 70 mol∼ Bi-30 mol∼ Sb alloy under a strong gravitational field of over 106 g level at maximum acceleration according to previous work of Mashimo et al. In this study, a simulation of the sedimentation process in the Bi-Sb alloy was performed using a self-consistent theory to discuss the diffusion mechanism. The simulation was performed first in an infinite radius range to confirm the validity of the simulation program. We simulated the sedimentation process in a finite radius range by changing the ratio between the diffusion coefficients for sedimentation and the internal chemical potential for comparison with the experimental results. The simulation result suggested that the diffusion coefficient for sedimentation was very large compared with that for conventional diffusion, even though substitutional solutes acted in this system. This indicated that the diffusion mechanism for sedimentation was different from the vacancy mechanism.