Various phase diagrams including an icosahedral (i-) phase in Al-Cu-Fe alloy system were examined in order to reveal the composition of the liquid in equilibrium with the Al64Cu23Fe13 i-phase. The i-phase was formed through the peritectic reaction between the liquid and the primary λ2-crystal. Prevention of the peritectic reaction was necessary to produce a single quasicrystal, however, there was a little compositional area of the molten alloy, which can crystallize the i-phase as a primary crystal. In the conventional solidification of Al60Cu37Fe3 alloy, almost primary crystalline particles were classified as i-phase, and the rests were λ2-phase. The λ2-particles acted as the inhomogeneous crystallization sites of an i-quasicrystal growth. So, several metallurgical treatments were tried to prevent the λ2-crystallization. Consequently, we found out an Al59Cu37Fe3Si1 molten alloy, which can crystallize the Al64Cu23Fe13 i-phase as a primary crystal at 978 K. The Al59Cu37Fe3Si1 molten alloy should be treated the preliminary cyclic melting process to prevent the λ2-crystallization. And we succeeded to grow up the large grained Al64Cu23Fe13 i-quasicrystal directly from the molten alloy.
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