Icosahedral and decagonal quasicrystals, crystalline phases, and multiple twins in rapidly solidified Al13Cr4Si4

Abstract

Both the icosahedral and decagonal phases have been found in Al13Cr4Si4 melt-spun ribbons. A definite orientation relationship existing between these two phases is determined by SAD which is the same as that obtained previously by Schaefer and Bendersky. During the icosahedral quasicrystal-crystal transformation in this Al−Cr−Si alloy, the Al13Cr4Si4 crystalline phase forms at low temperature and an unknown phase at high temperature. Both crystalline phases have definite orientation relationships with the icosahedral phase. The five-fold rotational twins of Al13Cr4Si4 around the [110] direction formed from the icosahedral phase follow the group-subgroup relationship. The unknown phase has a hexagonal lattice,a=0.73 andc=1.62nm.