Influence of electric field strength applied during the solution heat treatment of the Al–Mg–Si–Cu Alloy AA6111

Abstract In the present paper, the effect of electric field strength in the range E = 0.1 – 5.0 kV/cm applied during the solution heat treatment (SHT) of the AA6111 alloy at 475° –550 °C has been determined employing resistivity. An increase in the as-quenched resistivity ρ w occurred for all field strengths, the increase being relatively rapid up to E ≈ 1 kV/cm and only slight, if at all, for higher fields. Analysis of the results gave that the field reduced the enthalpy, entropy and Gibbs free energy of solution, the amount of reduction increasing with field strength. The electric current, which occurred with application of the field during SHT, ranged from (7 × 10 –3 to 4 × 102) μA, increasing with field strength and SHT temperature, but decreasing with time during the SHT. The role of the current in the enhancement of ρ w by the field is not clear.