Change in electrical resistivity during continuous heating of Cu₃Pd alloys quenched from various temperatures

Abstract

Electrical resistivity changes and thermal behaviour during continuous heating in Cu-12 at.%Pd and Cu-13at.% Pd alloys auenched from various temperatures are carefully examined and the relationships between the residual resistivity and the temperature coefficient of electrical resistivity and order parameter deduced from thermal measurement in this alloy system are experimentally investigated. The results are compared with reports published previously. The electrical measurement reveals that the value of electrical resistivity of these alloys increases just below the order-disorder transition temperature and the increase is greater than that in the Cu-15at.%Pd alloy reported previously. It is also shown that the residual resistivity essentially decreases with ordering and has an approximately linear relationship to the nth power of the order parameter S, where n tends to decrease from 5.2 to 2.8 with increasing Pd concentration. However, the temperature coefficient of resistivity has a linear relationship to S ² irrespective of alloy composition. Electrical resistivity versus temperature curves calculated using these relationships are in good agreement with that obtained from the electrical resistivity measurement for fully ordered and partially ordered samples. Furthermore, it is found that the difference between the electrical resistivity curves obtained by calculation and by measurement increases with increasing Pd concentration of the alloy.