Movement of Multiple Markers in Cu/Zn Multiple Phase Diffusion Couples and Its Numerical Analysis

Abstract

Movement of multiple markers (M-Ms) embedded in the Cu end member of a Cu/Zn multiple phases diffusion couple (M-couple) has been experimentally investigated at 623 K and the alignment of the M-Ms after diffusion anneal was reproduced by the numerical analysis that the authors have previously reported. Two intermediate phases, γ and ɛ, were found in the Cu/Zn M-couple. The M-Ms bent toward Zn side at Cu/γ phase interface and show almost a linear line in the γ phase. They again bent at γ/ɛ interface toward Zn side. The Kirkendall marker position, X k, locates in the ɛ phase layer. From this result, ratio, R = D Zn/D Cu, of the intrinsic diffusion coefficients with respect to the mole fixed frame of reference was determined to be about 46 at X k. On the assumption of a constant value of R = 46 in the ɛ phase and appropriate constant values of R = 10-1000 in the γ phase, alignments of M-Ms after diffusion anneal were numerically reproduced. By fitting the alignment of M-Ms obtained numerically on the experimental result, the value R in γ phase is estimated to be very large value of 500.