Resistivity measurements were carried out on quenched specimens of high-purity Al and dilute Al-0.0087at%Sc alloy in order to deduce the binding energy between Sc solute atoms and vacancies. The vacancy formation energy in pure Al was estimated to be equal to 0.79eV. This value was in good agreement with previously reported data. The apparent vacancy formation energy in the 0.0087at%Sc alloy was estimated to be equal to 0.6eV. This was somewhat lower than that in pure Al, and suggested the occurrence of vacancy-solute interactions in the alloy. On the basis of the experimentally determined vacancy formation energy in the pure Al and in the dilute Al-Sc alloy, the vacancy-Sc binding energy was deduced to be 0.35eV, by using the Lomer relationship. This value was rather large in comparison with those for other transition elements in Al. The high vacancy-Sc binding energy was suggested to be responsible for the characteristic effect of Sc upon precipitation behaviour in Al alloys.

Determination of Vacancy-Sc Interaction Energy by Electrical Resistivity Measurements. Y.Miura, C.H.Joh, T.Katsube: Materials Science Forum, 2000, 331-337, 1031-6