Interdiffusion in α solid solutions of the Cu-Zn-Sn system

The interdiffusion coefficients in the alpha fcc phase of Cu--Zn--Sn alloys, D exp Cu sub SnSn , D exp Cu sub SnZn , D exp Cu sub ZnZn and D exp Cu sub ZnSn , have been determined at 1073K. The concentration profiles indicate that the diffusion rate of Sn is greater than that of Zn in the Cu--Zn--Sn alloy. The diffusion paths show the typical S-shaped curves. All of the four interdiffusion coefficients are positive and they are very sensitive to the solute concentration. The atomic mobilities of the three diffusing elements in Kirkendall planes increase in the order of Cu, Zn, Sn. The interaction energy of the Cu--Sn bond is much larger than that of the Zn--Sn bond. From the results of the present work, it seems that the Onsager reciprocal relation holds in the alpha phase of the Cu--Zn--Sn system. 43 ref.--AA