Diffusion-coefficient measurements in liquid metallic alloys

被引:56
|
作者
Lee, JH
Liu, S
Miyahara, H
Trivedi, R [1 ]
机构
[1] Changwon Univ, Dept Met & Mat Sci, Chang Won 641773, South Korea
[2] US DOE, Ames Lab, Ames, IA 50011 USA
[3] Kyushu Univ, Dept Mat Sci & Engn, Fukuoka 812, Japan
[4] Iowa State Univ, Ames Lab, Ames, IA 50011 USA
关键词
D O I
10.1007/s11663-004-0085-6
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The value of the diffusion coefficient in the liquid (D-l) is generally obtained from the measurement of composition profiles ahead of a quenched planar interface. The experimental results show significant scatter. The main reason for this scatter will be shown to be due to the presence of fluid flow in the liquid. Directional-solidification studies in the Al-Cu system have been carried out to first establish the experimental conditions required for diffusive growth. The composition profiles are then measured to obtain the values of D-l for alloy compositions ranging from 4.0 to 24.0 wt pct Cu. The value of D-l = 2.4 X 10(-3) mm(2)/s was obtained along the liquidus line, and this result is significantly smaller than the values reported in the literature, which vary from 3.0 to 5.5 X 10(-3) mm(2)/s. It is shown that the scatter in the reported values can be correlated with the diameter of the sample used and, thus, with the fluid flow present in their experiments. Detailed experimental procedures to obtain and verify diffusive-growth conditions are outlined, and appropriate analyses of the data are discussed.
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页码:909 / 917
页数:9
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