Formation condition of the icosahedral phase in rapidly quenched Ag-In-RE (rare earth) alloys

• Published in: Philosophical magazine (2003. Print) 2006-01, Vol.86 (3-5), p.435-441
• Main Authors: Iwano, S., Nishimoto, K., Tamura, R., Takeuchi, S.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Quasicrystals; Semi-periodic solids; Structure of solids and liquids; crystallography
• ISSN: 1478-6435; 1478-6443
• DOI: 10.1080/14786430500253984

Formation of icosahedral (i) phases in rapidly quenched Ag-In-RE (rare earth) (RE = Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) ternary alloys is investigated. It is found that the relative magnitude of the quasilattice constant is well explained by the atomic radius of the RE elements for Ag-In-RE alloys with trivalent RE elements, and the formation of the i phase is governed by the atomic radius of the RE element. Moreover, the i phase is found to be formed in a wide composition range for the Ag/In atomic ratio but in a very narrow range for the RE concentration, which suggests that the RE concentration plays a crucial role in the formation, i.e. the stability, of the i phase rather than the average electrons-per-atom ratio. Furthermore, it is suggested that the structural change caused by the variation of the Ag/In concentration ratio in the i phase cannot be understood as a consequence of simple mutual replacement between Ag and In.