Icosahedral nanophases in the Al-Mn-Ce system

Nano-icosahedral phases were prepared by melt-spinning in the AlMnCe system (Al greater than or equal to 89 at.%). Ce-induced structure alterations ar e reported by x-ray diffraction for the icosahedral (i) AlMnCe phase. They comprise apparition of superstructure diffraction lines, due to chemical or dering in the 6-dimensional icosahedral lattice, which gradually changes fr om a simple to a face-centered (FCI) type. Also, strong anomalies of diffra cted intensities, with reference to model FCI phases, support Ce preferenti al location on a special set of sites. Microstructure investigations show a nanodispersion of i-AlMnCe in an Al-rich matrix, suggesting a low nucleati on barrier of this metastable phase in the melt.