Stabilization of icosahedral phase in Si substituted version of Al65Cu20Cr15 alloy

In order to find out the effect of Si on quasicrystalline (QC) and related phases, Si has been substituted in place of Al in Al-Cu-Cr system. In the p resent investigation, various alloys corresponding to Al65-xCu20Cr15Six (x = 1, 3, 5, 7 and 10) composition have been synthesized and characterized. T he investigations reveal that at 1 at.% Of Si both QC and crystalline (b.c. c., a = 8.90 Angstrom) phases are present but after annealing, the alloy be comes QC. The alloys having 3 at.% of Si has been found to show the formati on of icosahedral phase which exhibits high degree of disorder. At 7 at.% S i, the dissociation of the icosahedral phase commences. The dissociated pha ses have been found to be icosahedral and disordered diamond cubic phase (a = 7.87 Angstrom). At the highest silicon concentration (10 at.%) another c rystalline phase: primitive cubic phase (a approximate to 10.90 Angstrom) r esults along with the icosahedral phase. (C) 2001 Elsevier Science B.V. All rights reserved.