Effects of an external electric field applied during the solution heat treatment of the Al-Mg-Si-Cu alloy AA6111

Abstract

Abstract The application of an external dc electric field during the solution heat treatment (SHT) of AA6111 Al alloy increased the as-quenched resistivity ρ and hardness H v. The increases represented reductions in SHT of 10–20 K required for a constant ρ or H v. Analysis of the results gave that the field reduced both the enthalpy and entropy of solution. The resulting reduction in Gibbs free energy gave increases of 0.03–0.04 at.% in solubility of Mg2Si (or Al –Mg– Si – (Cu)-vacancy complexes) at 400 –600 °C, amounting to a factor of 33% increase in solubility at 400 °C and 6% at 600 °C.