Frozen-in vacancies and the recovery were investigated in some Cu-based dilute alloys by using positron annihilation lifetime spectroscopy. Cu-0.5at%Sb, Cu-0.5at%Sn and Cu-0.5at%In dilute bulk alloys were quenched to ice water from 1223K. A pure-Cu specimen was also quenched from the same temperature. As a result, no frozen-in vacancies were detected in as-quenched pure-Cu specimen. On the other hand, as-quenched Cu-0.5at%Sb alloy contained frozen-in thermal equilibrium vacancies with concentration of 3 x 10−5. Furthermore, these frozen-in vacancies in Cu-0.5at%Sb alloy were stable until 473K, and began to migrate at 523K. Finally, the Cu-Sb alloy were recovered to the fully annealed state at 823K. This thermal stability clearly implies some interaction exists between a vacancy and Sb atom and due to the interaction, thermal equilibrium vacancies were trapped by Sb atoms during quenching.

Vacancy Trapping by Solute Atoms during Quenching in Cu-Based Dilute Alloys Studied by Positron Annihilation Spectroscopy. A.Yabuuchi, Y.Yamamoto, J.Ohira, K.Sugita, M.Mizuno, H.Araki, Y.Shirai: Journal of Physics - Conference Series, 2009, 191[1], 012019