Interdiffusion in the intermetallic compound β-AgMg

Interdiffusion coefficients, D̃, in the β-AgMg phase from 42 to 52 at% Mg have been determined by Matano's method in the temperature range between 723 and 973 K with semi-infinite couples consisting of β-AgMg alloys. D̃ decreases with increase of the liquidus temperature and shows a minimum at 47 at% Mg which deviates slightly from the stoichiometric composition. D̃ is about one order of magnitude larger than the self-diffusion coefficient of silver in the whole concentration range of the β-AgMg phase. This difference can be attributed to the large thermodynamic factor for interdiffusion in the β-AgMg phase. The activation energy for the interdiffusion is nearly equal to that for the self-diffusion of silver, while the pre-exponential factor for the interdiffusion is about one order of magnitude larger than that for the self-diffusion of silver in the β-AgMg phase.