Solidification of Al₆₅Cu₂₀Co₁₅ and Al₆₅Cu₁₅Co₂₀ alloys

The solidification behavior of Al₆₅Cu₂₀Co₁₅ and Al₆₅Cu₁₅Co₂₀ alloys was studied by means of scanning electron microscopy, energy-dispersive x-ray analysis, powder x-ray diffraction, and differential thermal analysis. Slowly cooled as well as rapidly cooled ingots of both alloys contained a decagonal quasicrystalline phase as dominant phase with additions of several minor normal-crystalline phases. The decagonal phase was found to solidify in a temperature range limited by two peritectic reactions involving phases of CsCl-type structure. Formation of AlCu and Al₂Cu phases was also observed.