The thermoelastic phase transition in Au—Cd alloys studied by acoustic emission

Abstract

The acoustic emission generated during the thermoelastic phase transitions in polycrystalline Au–47·5 at.% Cd and in Au–49 at.% Cd alloys has been recorded and analysed. It was found that the amount of acoustic activity depends upon the direction of the transformation, the heating or cooling rates, and the specific crystallographic features of the martensitic phases. Precursor acoustic activity was detected in both alloys at temperature differences of about 2 5°C before the M ₈ point. The dynamics and kinetics of martensitic thermoelastic phase transformations are discussed in terms of the accompanying generation of acoustic emission.