Cluster line criterion and Cu–Zr–Al bulk metallic glass formation

✍ Scribed by Qing Wang; Chuang Dong; Jianbing Qiang; Yingmin Wang

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 438 KB
• Volume: 449-451
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2006.02.271

✦ Synopsis

The cluster line approach is presented and applied for searching the optimum glass-forming composition in the Cu-Zr-Al system. Three cluster selection rules are proposed: topologically dense packing (atomic size-related), chemical short-range order as evaluated by dissimilar atomic pairs, and composition distance to deep eutectics. Three Cu-Zr clusters Cu 8 Zr 5 , Cu 6 Zr 5 and Cu 5 Zr 6 satisfy all the three rules and are selected to construct cluster lines. The bulk metallic glass-forming range in the Cu-Zr-Al ternary system is thus determined. It is found that the thermal stabilities and glass-forming abilities of the bulk metallic glasses manifest monotonously increased tendencies with the increased Al content. The optimum Cu-rich and Zr-rich bulk metallic glass compositions are Cu 58.1 Zr 35.9 Al 6 and Cu 39.7 Zr 47.1 Al 13.2 (number indicate at.%) and they are, respectively, located along the Cu 61.8 Zr 38.2 -Al and Cu 45.7 Zr 54.3 -Al cluster lines, where the deep eutectics exactly correspond to the dense packing clusters Cu 8 Zr 5 and Cu 5 Zr 6 . The characteristic parameters (glass transition temperature T g and melting temperature T l ) of Cu 58.