Phase transformations in mechanically alloyed Al-Cu-Cr powders

Abstract

Mechanical alloying was used 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 0C 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 0C 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 0С. Further increase in the annealing temperature results in the quasicrystalline phase transformation into ψ-Al65Cu25Cr10 phase, which is an approximant phase to icosahedral quasicrystal.