High strength Al-alloys with nano-quasicrystalline phase as main component

The formation of quasicrystals by ball milling as well as by rapid quenchin g in the systems AlMnCe and AlMnFe was investigated. Melt spinning resulted in a nanoscale mixed structure of up to 60 vol.% quasicrystalline particle s embedded in a fee AI-matrix revealing a strong influence of the alloy com position on the solidification behaviour. Milling leads to the formation of an amorphous phase, however, there was no significant effect for Ce additi on on phase formation. While the use of process-control agent or different milling atmospheres mainly affects the powder morphology, the milling inten sity and, hence, the temperature during milling was found to be the most im portant parameter concerning phase evolution. The nature of observed metast able phase transitions was clarified by DSC measurements combined with x-ra y diffraction. (C) 1999 Acta Metallurgica Inc.