Formation of decagonal quasicrystals in mechanically alloyed Al–Cu–Cr powders

Abstract

Abstract Mechanical alloying was applied to form a decagonal phase in the Al–Cu–Cr system. Elemental powders of Al67Cu20Cr13, Al75Cu10Cr15, Al65Cu24Cr11, Al69Cu21Cr10 and Al78Cu10Cr12 compositions (in at%) were mechanically alloyed in a planetary ball mill. Annealing in the temperature range of 500 to 550 °C results in the formation of binary and ternary compounds including the decagonal quasicrystalline phase that was found to be stable at least up to 800 °C and was present in various amounts in all investigated alloys. No icosahedral quasicrystalline phase was found in the samples. The maximum content (95 vol%;) of decagonal quasicrystalline phase was observed for Al69Cu21Cr10 compound annealed at 635 °C. Further increase in the annealing temperature results in the quasicrystalline phase transformation into ψ-Al65Cu25Cr10 phase, which is an approximant phase to icosahedral quasicrystal.