Specific heat capacities of Fe-Co-Cr-Mo-C-B-Y bulk metallic glasses and their correlation with glass-forming ability

The practical applications of Fe-based bulk metallic glasses (BMGs) have been seriously restricted due to their small critical sizes. Understanding the underlying factors governing the glass-forming ability (GFA) of Fe-based BMGs is the essence to solve this problem. Here, the specific heat capacities (Cp) of amorphous and crystalline Fe-Co-Cr-Mo-C-B-Y alloys have been investigated in detail. A parameter, configurational entropy, based on the difference in Cp between BMG and its crystalline counterpart, has been used to correlate with GFA. The alloy containing 7% Co with the lowest configurational entropy is expected to possess the highest viscosity and most ordered atomic structure, which may stabilize the glassy structure, resisting the crystallization and thus enhancing the glass-forming ability of Fe-based BMGs.