Diffusion Mechanism of Atoms in Ordered Alloys at Low Temperature

低温有序合金中原子的扩散机制

基本信息

批准号：
02805081
负责人：
HASAKA Masayuki
金额：
$ 1.15万
依托单位：
Nagasaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

The knowledge of diffusion phenomena of atoms is essential to develop new materials for modern technologies and then to use safely mechanical and electrical equipments made from those highly designed materials. The sufficient resolution of secondary iron mass spectroscopy has proved to be available for determining the small diffusion coefficients and the isotope effects of many atoms down to relatively ll"ow temperature. Our research clarified the small diffusivities and the isotope effects and the diffusion mechanisms of several solute atoms in the ordered alloys of B2, DO_3 and L1_0 types at low temperatures, by using the profit of secondary ion mass spectroscopy. The main results obtained are as follows. The temperature dependences-of diffusivities of nickel, vanadium, titanium and boron in theFe-Al alloy were not explained by a simple Arrhenius relation. The diffusivities of vanadium, titanium and boron were controlled by the change of B2 order, while the diffusivity of nickel was determined by the changes of DO_3 order as well as B2 order. The isotope effect of boron was about 0.2 in the disordered state and the ordered states of B2 and DO_3 types in the Fe-Al alloy. The diffusion of boron proceeded through highly correlated mechanism in the Fe-Al alloy. The diffusivity of boron in the ordered state of the CuAu alloy was not smaller than that extrapolated from the disordered state. The isotope effect of boron in the CuAu alloy was 0.1 in the disordered state and 0.8 in the ordered state of L1_0 type. Correlation for the diffusion of boron was stronger in the disordered state than in the ordered state.

原子扩散现象的知识对于开发现代技术的新材料以及安全地使用由这些精心设计的材料制成的机械和电气设备至关重要。二次铁质谱的足够分辨率已被证明可用于确定许多原子在较低温度下的小扩散系数和同位素效应。我们的研究阐明了几种原子的小扩散系数和同位素效应以及扩散机制。利用二次离子质谱分析了B2、DO_3和L1_0型有序合金中的溶质原子，得到的主要结果如下： Fe-Al合金中的钒、钛、硼不能用简单的阿累尼乌斯关系来解释，钒、钛、硼的扩散系数是由B2级数的变化控制的，而镍的扩散系数是由DO_3级数的变化决定的：硼在Fe-Al合金中的无序态和有序态的同位素效应约为0.2。在 Fe-Al 合金中通过高度相关的机制进行。 CuAu合金有序状态下硼的扩散系数不小于从无序状态推断的扩散系数。 L1_0型CuAu合金中硼的同位素效应在无序状态下为0.1，在有序状态下为0.8。硼扩散的相关性在无序状态下比在有序状态下更强。