The microstructure analysis of Al-Cu-Cr phases in Al65Cu20Cr15 quasicrystalline particles/Al base compotites

摘要

The microstructures of Al65Cu20Cr15 as-cast and as-quenched master alloys and Al-Cu-Cr phasesin Al65Cu20Cr15 particles/Al base composites afterhot-pressing are investigated by transmissionelectron microscopy and electron probe microanalyser.Two icosahedral quasicrystals SIQC and FIQC, twoapproximants to icosahedral quasicrystal IIA and FIA,one decagonal quasicrystal DQC, three approximants todecagonal quasicrystal DAI, DA2 and Θ, a new Al-Cuphase ξ that have a monoclinic structure with latticeparameter a=1.2nm, b=0.9nm, c=0.8nm, β=130° andthree τ type phase τ2, τ4 and τ7 were found. Thecomposition-structure diagram in the Al-Cu-Cr systemwas drawn from phases above, in which three are twoe/a-constant lines: one is the icosahedralquasicrystalline line with e/a=1.86; the other is thedecagonal quasicrystalline line with e/a=2.09.