Abstract
A numerical analysis was carried out to examine the solidification effect on the concentration distribution of a solute in an Ag/Ag–5 at%Au diffusion couple in a liquid diffusion experiment using the long capillary method. Shrinkage-induced fluid flow in the solidifying sample was calculated, and the solute movement due to the fluid flow was evaluated. In the analysis, molten samples in a graphite crucible were cooled in air at three different cooling rates. Flat isoconcentration contours in the horizontal plane of the diffusion couple were formed in the sample with a low cooling rate, whereas concave isoconcentration contours were formed in the samples with high cooling rates. Those features in the simulation agreed with the experimental results. The optimum conditions to avoid the solidification effect in liquid diffusion experiments are discussed.
