On some discrepancies in the literature about the formation of icosahedral quasi-crystal in Al-Cu-Fe alloys

To clarify some discrepancies in the literature about the formation of icosahedral quasi-crystal (IQC) in Al-Cu-Fe alloys, microstructures, and constituent phases of Al62.5Cu25Fe12.5 and Al65Cu20Fe15 alloys were studied, Each dendritic arm of the primarily solidified lambda -Al13Fe4 phase is a single crystal that possesses no definite orientation relationship with the IQC, formed by peritectic reaction (L + lambda + beta --> IQC) or a solid-state reaction (Cu-rich phases + lambda + beta --> IQC), This fact disproves an assumption that h-phase is an approximant of the IQC, Two types of cubic phase, beta -phase with CsCl structure containing more Fe and tau (3) phase, which is a superstructure and contains less Fe, were observed depending on the composition and thermal history of the samples.