THE POST-QUENCH VACANCY BEHAVIOR IN BETA-CU-ZN-AL ALLOY

Positron lifetime spectroscopy is used to study the long time room tem perature behavior of defects retained after quench in beta-Cu-Zn-Al si ngle crystals. Quenching treatments are made in a temperature range fr om 493 to 1073 K. The decay in the defect concentration with the aging time is attributed to the motion of vacancies to sinks. Assuming the sinks as dislocations, a dislocation density is derived. This density increases with increasing quenching temperature. We find that after lo ng time aging all vacancies disappear for all T(q) used in this work e xcept for 773 K. This behavior is associated to the existence of gamma -phase precipitates which are known to be present after quench from th is temperature.