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Effect of Fe Substitution on the Stabilization of the Icosahedral Phase in Al‐Cu‐V alloys
Author(s) -
Misra D.K.,
Tiwari R.S.,
Srivastava O.N.
Publication year - 2001
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/1521-4079(200106)36:4/5<419::aid-crat419>3.0.co;2-q
Subject(s) - icosahedral symmetry , alloy , crystallography , materials science , transmission electron microscopy , annealing (glass) , quasicrystal , diffraction , phase (matter) , electron diffraction , electron microscope , scattering , condensed matter physics , metallurgy , chemistry , optics , nanotechnology , physics , organic chemistry
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‐x Cu 15+x Fe 5 V 5 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 θ‐Al 2 Cu phases along with the i‐phase. The nanoquasicrystalline and α‐Al phases in Al 75 Cu 15 Fe 5 V 5 alloy transform to Al 7 Cu 2 Fe 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 Al 65 Cu 25 Fe 5 V 5 alloy. The angles and details of twelve sectors are varying alternatively. A plausible explanation in terms of microtwin domains of θ‐Al 2 Cu structure in [ $\bar 1$ 10] orientation has been given to explain the characteristic features of the pseudo‐twelve fold pattern.