Interdiffusion in Al-Cu-Mg Alloys under High Pressure

Abstract

The interdiffusion coefficients in the α fcc phase of Al-Cu-Mg alloys have been determined under pressures from 0.101 to 3000 MPa in the temperature range from 793 to 853 K. The direct and indirect interdiffusion coefficients are positive. The diffusion coefficients decrease with increasing pressure. The activation energies for interdiffusion and impurity diffusion increase with pressure. The ratios of the activation volumes to the molar volume of aluminum are between 1.01 and 1.08. It is concluded that the diffusion of copper and magnesium in the Al-Cu-Mg alloy occurs predominantly by the monovacancy mechanism.