Anomalous Behaviour of Electrical Resistivity and Elastic Constants in Quenched β (Au–Cd)+Cu Alloys

Measurements of electrical resistivity and elastic constants in quenched Au-47.5 at%Cd-0.75 at%Cu and Au-49.0 at%Cd-0.75 at%Cu alloys have been carried out as a function of temperature The resistivity behaviour is almost the same as that in a series of βAu–Cd binary alloys reported previously; it has been observed that the resistivity anomaly occurs at about 380 K for both alloys. In the quenched Au-47.5 at%Cd-0.75 at%Cu alloy, the elastic constants C′=(C11−C12)⁄2 and C44 have also exhibited anomalous behaviour at about 380 K: the C′ decreases drastically and the C44 increases slightly at this temperature. It has been found, on the other hand, that in the quenched Au-49.0 at%Cd-0.75 at%Cu alloy, there is no anomaly in the elastic constants C′ and C44 at about 380 K in spite of the occurrence of the remarkable resistivity anomaly.The modification of the martensitic transformation in βAu–Cd alloys by quenching is discussed on the basis of these results, and a possible explanation of the effect of quenching on the martensitic transformation is presented.