Formation of icosahedral quasicrystals in (Ag,Au)-based ternary systems

Abstract We investigated the phase constitution of rapidly solidified (Ag,Au)-based ternary alloys at various compositions of (M,X) 85.7 RE 14.3 (M = Ag, Au, X = Al,Ga,In, RE = Er,Lu). It is found that an icosahedral phase is formed at an average electrons per atom ratio close to 2.0 as well as at the composition ratio of (M,X) 6 RE, suggesting that these factors have crucial roles in the stability of the icosahedral phases. It is also found that the trend of the icosahedral phase formation in the Au-based alloys is quite different from that in the Ag-based alloys.