Aging behavior in Cu-Al-Be shape memory alloy

Abstract

This article reports positron annihilation spectroscopy and calorimetric measurements of the aging behavior in a Cu-Al-Be shape memory alloy. An excess of single vacancies is retained in the alloy as a result of a quench. All vacancies in excess disappear after long aging time, and a migration energy EM=1.0±0.1eV for this process has been found to be larger than in other Cu-based shape memory alloys. The good correlation found for the concentration of vacancies and the shift in the martensitic transition temperature demonstrates that, in Cu-Al-Be, changes in the transition after a quench are deeply related to the excess of vacancies. © 1999 American Institute of Physics.