Theta-prime precipitation in aluminium-copper-cadmium alloys

摘要: Abstract Dilatometer, resistivity and electron microscope measurements have been used to study the nucleation growth of θ′ phase in an Al-5.12% Cu-0.14% Cd alloy. The results suggested that took place by coalescence mobile copper-cadmium-vacancy clusters, activation energy for process being 0.5 eV. characteristics precipitate could all be satisfactorily explained assuming was controlled movement clusters it. During early stages ageing were rich vacancies so rapid. In later contained less per solute atom consequence their became more sluggish which resulted very slow growth. When extensive Cd′ precipitation started occur cadmium atoms left therefore dispersed thus allowed rapid precipitates. varied from 0.7 eV ageing, 1.5 stages.