Evaluation of glass-forming ability of binary metallic glasses with liquidus temperature, crystallographic data from binary phase diagrams and molecular dynamics simulations

Abstract

The glass-forming ability (GFA) of binary metallic glasses was analyzed with data for the liquidus temperature ( T l) acquired as a function of composition from binary phase diagrams, assisted by crystallographic data combined with amorphous-forming composition range (AFCR) and molecular dynamics (MD) simulations. A necessary condition for the formation of bulk metallic glasses (BMGs) was determined as Δ T l ≥ 300 K where Δ T l was defined as a decrease in T l due to eutectic reaction. The crystalline compounds with structure types of bcc or its derivative type, such as CsCl (B2), CrB (B f), Al 2Cu (C16) and MoSi 2 (C11 b), tended to be found in AFCR frequently. The total pair-distribution and interference functions revealed a high forming tendency of a noncrystalline Cu 10Zr 7 structure created by MD. Simultaneous achievements of the Cu 10Zr 7 structure for crystallographic features resulting from the bcc family structure and geometrical features in phase diagram for T l affect the formation of Cu 61.8Zr 38.2 BMG.