Phase formation and growth in Al–Mg couple with an electromagnetic field

Abstract

The influence of alternative magnetic field on the formation and growth of the intermediate phases in Al–Mg diffusion couple was studied in this paper. The diffusion zone is composed of two intermediate phases, namely β and γ. Thickness of each intermediate phase is examined. The results show that the alternative magnetic field increased the thickness of β and γ phases; the layer growth of β and γ phases obeys the parabolic rate law with the magnetic field. The growth rate of the β and γ phases increased with the application of the alternative magnetic field. This change is manifested through a change in the frequency factor k 0 but not through a change in the activation energy Q and the effect depends on the arrangement of the specimens in the magnetic field. The frequency factor k 0 for intermediate phase layer growth with an alternative magnetic field was 39.95 cm 2/s (perpendicular) and 26.02 cm 2/s (parallel) for γ phase and 2.84×10 −4 cm 2/s (perpendicular) and 2.57×10 −4 cm 2/s (parallel) for β phase compared with those without an alternative magnetic field 22.4 cm 2/s for γ phase and 1.53×10 −4 cm 2/s for β phase.