Alteration in Al Concentration Occasioned by the Ordering Reaction in Cu-Al Binary Alloys

Abstract

The authors have been studying on the complicated phase transformations occuring in Cu-Al binary alloys by means of the dilatometric and the electric specific resistance measurements. In this report, the specific-heat measurement was carried out to account for the cause of an alteration in Al concentration which appeared in several heat-treatments, namely, in the case of air-cooling and furnace-cooling from the β phase and in the case of the reversible treatment of the β′ martensite respectively. As a result of the experiments, it was found out that the ordering reaction, Cu₃Al, advanced quickly during the above treatments, resulting, in the alteration in Al concentration and Ms point, and the β′ martensite containing the Al concentration close 12.4 wt%, the Cu₃Al composition, coming into formation.