Compositions design of Co-Fe-based bulk metallic alloys

Abstract

Glass forming ability (GFA) is one of the key factors hindering the application of bulk metallic glasses (BMGs). In this paper, a cluster-related method was used to design good glass-formers in the complex Co-Fe-based system. A novel Co-centered Co-Mo binary topologically packed cluster Co-Co _8 Mo _4 with 12-coordination number was found and used. The basic ternary composition in Co-Mo-B system is calculated based on an intersection of cluster lines B-B _2 Co _8 and Co-Co _8 Mo _4 . Based on this, a series of novel Co-Fe-based glass-formers with high GFA, were quickly designed using the method of similar element replacement and microalloying. The best glass-former is (Co _27.5 Fe _27.5 Mo _12.2 Cr _12.2 B _16 P _4.6 ) _98 Y _2 . The source of high GFA of designed glass-formers was also discussed. The results of this paper would offer researchers a novel insight in understanding the source of high GFA of Co/Fe-based system, and lay a solid foundation for exploring Co/Fe-Mo-based glass-formers via newly found Co-Mo binary cluster.

Keywords

• bulk metallic glass
• compositions design
• Co-Fe based alloys
• amorphous alloys