Al-Mn-Ce quasicrystalline composites: phase formation and mechanical properties

Aluminium-based composites with quasicrystalline particles as reinforcements were synthesized via the powder metallurgy processing route. In order to obtain bulk samples with a nanoscale microstructure most equivalent to that resulting from rapid solidification, powders of Al-Mn-Ce alloys were prepared by pulverization of melt-spun ribbons using a planetary ball mill. Significant differences in the phase formation upon quenching, composite microstructure and thermal stability of the microstructure were found for different alloy compositions. Severe grain growth during the subsequent consolidation by hot extrusion caused the formation of a micrometre-scale composite instead of the nanoscale phase mixture initially existing after rapid solidification. After hot extrusion, the specimens were deformed by compression at a constant compression rate at room temperature. With an ultimate strength of up to 975 MPa and a ductility of more than 4% the material yields excellent properties compared with conventionally produced aluminium-based alloys.