Abstract:Ultrafine powders of Al-Cu alloy were prepared by gas evaporation process, formation law of the phases in the as-prepared powders were examined. The results showed that the phases formed in ultrafine powders are within the scope of the phases given in Al-Cu alloy phase diagram. There are onlyθ-CuAl₂,γ₂-Al₄Cu₉,β-AlCu₃ alloy phases formed in the tested powders. The kinds of the phases formed in the powders and their fractions are controlled by the pressure fraction of the components in the mixed vapor and the cooling conditions of the experimental equipment. Changing pressure of Ar gas could only change the fractions of different phases in the powders. The solid solubility of Al and Cu atoms in the lattice of phase Cu and phase Al in the powders was within the scope of that in Al-Cu alloy diagram. The structure of the phases in the as-prepared powders were in equilibrium state.

Key words: gas evaporation　vapor condensation　ultrafine powders　alloy powder