Phase transition effects of the Mg-Cd system on the positron annihilation parameters

Positron annihilation measurements made on Mg-Cd alloys are considered. Some pronounced effects at the order-disorder transition were found when the alloy composition was close to stoichiometry. No apparent effects of the order-disorder transformation were exhibited when the alloy was far from the stoichiometric composition. The measured mono-vacancy energies of the system at the stoichiometric composition showed a pronounced decrease when the alloy passed from an ordered to a disordered state.