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-Co8Mo4 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-B2Co8 and Co-Co8Mo4. 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 (Co27.5Fe27.5Mo12.2Cr12.2B16P4.6)98Y2. 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.

Viscosity of Al–Ni–Co–Nd(Sm) glass-forming melts at high temperatures

“…One of the main aim is to find compositions with high glass-forming ability (GFA) and thermal stability [9][10][11][12][13][14]. However, the existing GFA criteria have no predictive function, and their calculation is possible after obtaining samples in amorphous state only [15][16][17][18]. In addition, it is known that aluminum-based alloys with transition (TM) and rare-earth metals (R) remain highly inhomogeneous systems even at significant overheatings above liquidus temperature (see, for example, [19][20][21][22][23]); it means that special melt treatment before rapid quenching is required.…”