Abstract
The phase diagram, mainly in the Al corner, of the Al-θ-Cd system was studied by electrical resistivity and lattice spacing measurements, thermal analysis and microscopic observation. In addition, the solubility of Cu in Al with 0.02 to 0.3wt% Cd was determined. The results obtained are as follows:
(1) The θ-Cd alloys in the Al-θ-Cd system was considered as a pseudo-binary system. It was concluded that this system had a monotectic reaction expressed as L1_??_L2 + θ at 580°C.
(2) The monotecto-eutectic reaction of the Al-θ-Cd system, L1_??_L2 + Al + θ, occurred at 544°C. This nonvariant reaction was characterized by 27wt%Cu, 18wt%Cd and the rest of Al.
(3) The isothermal cross sections diagram at 520°C showed that the addition of Cd had little effect on the solubility of Cu in the Al-Cu-Cd alloy.
(4) It was suggested that aging suppression in Al-Cu-Cd alloys was not explained by assuming significant decrease of Cu content in the solid solution of Al.
