Vacancy-Impurity Binding Energy in Aluminum—1.7 at.% Zinc Using Positron-Annihilation Lifetimes

Positron-annihilation lifetimes were measured in pure aluminum and in aluminum---1.7 at.% zinc at temperatures between 20 and 550^∘{}C. The data were analyzed using an extension of the trapping model to obtain the vacancy formation energy in aluminum (EF=0.62±0.02 eV). Under certain restrictive assumptions the binding energy of vacancies to zinc atoms in aluminum was found to be EB=0.019±0.004 eV. A relaxation of these assumptions yielded only an upper bound (EB<0.04 eV).