Current dependence of the retardation of precipitation by direct-current stress in Al-3.3 at% Mg

Abstract

The effect of direct current (d.c.) stress on the precipitation kinetics in an Al-3.3 at% Mg alloy was investigated by the resistometric method. The reaction rate of the precipitation was found to be retarded by direct current (d.c.) stress, and the result is discussed in terms of the current-assisted-vacancy-annihilation model, which the authors have proposed to interpret the result obtained in Al-5.6 at% Zn and Al-1.8 at% Cu alloys. As a result of subtracting the apparent accelerating effect due to Joule heating, the retarding effect turns out to show a non-linear current dependence in the range of current densities from 4000 to 7000 Acm−2 although it varies linearly up to 3000 Acm−2.