The effect of Fe substitution on the formation and stabilization of icosahedral phase in Al-Cu-V alloys has been investigated by employing transmission electron microscope and X-ray diffraction. In the as quenched Al_75-xCu_15+xFe₅V₅ alloys with x=0,5 and 10 it has been found that grain size of icosahedral phase increases from 156nm to 0.53µm with increasing x. All the three alloys exhibit the formation of α -Al and theta -Al₂Cu phases along with the i-phase. The nanoquasicrystalline and α -Al phases in Al₇₅Cu₁₅Fe₅V₅ alloy transform to Al₇Cu₂Fe phase by annealing at 550°C for 4 hrs by peritectic type of reaction. A curious type of pseudo-twelve fold electron diffraction pattern devoid of any diffuse scattering has been observed in some local regions of Al₆₅Cu₂₅Fe₅V₅ alloy. The angles and details of twelve sectors are varying alternatively. A plausible explanation in terms of microtwin domains of theta-Al₂Cu structure in [-110] orientation has been given to explain the characteristic features of the pseudo-twelve fold pattern.

Keywords: Fe substitution, icosahedral phase, Al-Cu-V

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