LAUSR

Abstract The influence of Cr and Ni additions in rapidly-solidified Al-Cu-Fe alloys was investigated. Four compositions, namely, Al 64 Cu 20 Fe 13 Ni 3 , Al 63 Cu 18 Fe 10 Ni 9 , Al 65 Cu 22 Fe 10 Cr 3 and Al 67 Cu 20 Fe 5 Cr 8 were selected based on a methodology in which the average valence electron per atom (e/a) ratio of the ternary Al-Cu-Fe quasicrystal was maintained constant. Melt-spun ribbons of all four alloys were produced and then examined by X-ray diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy. The results indicate that the Al-Cu-Fe icosahedral quasicrystalline phase has limited solubility for Ni such that with increasing Ni content, the fraction of the quasicrystalline phase decreased drastically and two primitive B2 cubic phases were formed instead. Additions of Cr resulted in the formation of a decagonal quasicrystal at the expense of the icosahedral phase. At 3 at% Cr, both icosahedral and decagonal phases were observed, with the former having the major volume fraction. For the alloy containing 8 at% Cr, only the decagonal phase was observed.