A reduction of the stored energy in Cu processed by equal-channel angular pressing was observed after 4 years of storage at room temperature. It was found that the decrease of stored energy was most probably caused by the loss of excess vacancies.

Reduction of Vacancy Concentration during Storage of Severely Deformed Cu. J.Gubicza, S.V.Dobatkin, E.Khosravi: Materials Science and Engineering A, 2010, 527[21-22], 6102-4