On the Superstructure of the Ordered Alloy Cu₃Pd. III. High Temperature Electron Diffraction Study

Abstract

Using a high temperature electron diffraction camera, Cu 3 Pd alloys have been investigated in thin oriented, evaporated films at temperatures below and above the critical point of order-disorder. The present work has elucidated that, in alloys of α''-phase, the line-up number of anti-phase domains and the degree of order inside domains decrease with increasing temperature in the range of 20∼40°C below the critical point, and an abrupt decrease of the line-up number of domains occurs at the critical point. In the range of 100∼150°C above the critical point, short chains of one-dimensional anti-phase domains with the same period of out-of-steps as in the ordered state remain randomly in an equilibrium state. On the other hand, anti-phase domains are absent in the alloys of α'-phase below as well as above the critical point.