Crystal-quasicrystal local structural transition in Al-Cu-Fe

The rearrangement of the local environments of copper and iron in the ternary alloy Al₆₅Cu₂₂Fe₁₃ in transition from a crystalline phase to a quasicrystalline phase has been studied by combined extended x-ray absorption fine structure (EXAFS) and x-ray absorption near-edge structure (XANES) analysis. It has been found that the nearest environment of copper retains symmetry characteristic of a crystal; however, a turn and small shifts of copper matrix atoms causes a considerable rearrangement of aluminum atoms around iron. As a result, icosahedral clusters with pentagonal symmetry are formed around iron atoms, and translational symmetry breaking is accompanied by the transition of Al₆₅Cu₂₂Fe₁₃ to a quasicrystalline state.