Elastic Behavior and Phase Stability of the β1-AgZn Alloy

To elucidate the dynamical mechanism of the β 1 to ζ transition the elastic constants of metastable β 1 phase of Ag-Zn alloys containing 46.5 and 48.5 at.% Zn are measured in the range between room temperature and the β 1 to ζ transition temperature using an ultrasonic pulse-echo overlapping method. The elastic constants C L [110]=(C 11 +C 12 +2C 44 )/2 and C 44 decrease linearly with increasing temperature up to 340 K and then fall more rapidly on further heating. On the other hand, C 11 decreases linearly on heating up to 340 K and then increases at higher temperatures. Furthermore, C L [111]=(C 11 +2C 12 +4C 44 )/3 which is mainly related to the β 1 to ζ transition mechanisum decreases rapidly above 340 K. These elastic constants show a characteristic temperature hysteresis with heating and cooling. Based on the obtained results, we discuss the transition mechanism and stability of the β 1 phase.