The influence of an
alternative magnetic field on the structure and growth of the intermediate phase in Al Mg diffusion
couple was studied. The experimental results show that electromagnetic field increases the thickness of the intermediate phase, namely β and γ phase, and the effects increase with the intensity and frequency of the electromagnetic field. The
parabolic rate law is obeyed in the growth of the layer β and γ phases in the Al Mg diffusion couple. The frequency factor( k 0) and the activation energy for intermediate phases growth with and without electromagnetic field were calculated. The influence of the electromagnetic field is mainly on the pre exponential frequency factor and not on the activation energy for the process. It suggests that the effect of the electromagnetic field is to increase the frequency of the atoms involved in the thermally activated process and/or the activation entropy rather than the barrier height. Entropy will increase if the AC magnetic field increases the degrees of freedom at the saddle position in the thermally activated event. As a result, the diffusion process of atoms is promoted and the growth rate of the intermediate phases is increased.