Bulk metallic glass-forming region of Cu-Zr binary and Cu-Zr based multicomponent alloy systems

We have evaluated the predictive ability of a simple method combing topological and chemical analysis with the normalized configurational entropy S-config/R in rapidly locating the bulk metallic glass-forming composition region, in Cu-Zr binary and Cu-Zr-Ti, Cu-Zr-Al, Cu-Zr-Ni-Ti, Cu-Zr-Ni-Al-Ti multicomponent alloy systems. It was found that the chemical mixing enthalpy between constituents and efficient cluster packing are two dominate factors in BMG formation, and BMGs form in composition region with S-config/R ranging from about 0.8 to about 1. The predicted composition regions of bulk metallic glasses (BMGs) are in good agreement with experimental results. BMG formation is most probably a compromise between topological and chemical effects. BMGs can form with efficient cluster packing, even they are not the most thermodynamically stable ones. At the same time, BMGs can also form with large negative chemical mixing enthalpy, even they are not the most efficiently packed ones. This method could be used to rapidly locate BMG-forming composition region, especially when eutectic composition is unknown. (C) 2008 Elsevier B.V. All rights reserved.