Abstract
Electrical techniques have been used to study the thermal vacancies in 401.0 casting aluminum alloy. Quenching experiments were usually performed on thin specimens to ensure a uniform quenching rate throughout the specimen. After grinding, polishing and etching, samples of 401.0 were homogenized for 12h at 673K and annealed for 90min., before quenched in water (277K) and then subjected to electrical measurements. From such measurements it is possible to deduce the vacancy formation enthalpy, which in combination with the results of self-diffusion measurements, give a value for the migration enthalpy of the vacancy.