An isothermal anneal study of quenched and cold-worked copper-palladium alloys

Abstract

The annealing behavior of quenched and cold-worked copper-palladium alloys in the composition range from 6 to 30 atomic per cent palladium has been studied at temperatures from room temperature to 450°C. It is concluded that ordering probably takes place by a nucleation and growth process. The growth of ordered domains is a singly activated process with activation energies in the range from 34 to 46 kcal/mol, depending on the composition and the condition of the sample. Nucleation is probably not a singly activated process, but the “average” activation energy in the temperature range considered is of the order of 20 kcal/mol. A survey of the order-disorder phenomena in light of the present data suggests that the phase diagram is in need of serious revision. The probable form of the revised diagram is discussed.