Effect of solute atoms on glass-forming ability for Fe-Y-B alloy: An ab initio molecular dynamics study

The glass-forming abilities of Fe78B22, Fe70Y6B24, Fe72Y6B22 and Fe72.5Y3.5B24 alloys were characterized comprehensively using ab initio molecular dynamics simulations. The calculated results were correlated with the properties and atomic structures. It was found that the Fe72Y6B22 alloy consists of both the most stable and the least deformed body centered cubic atomic packing structures in the supercooled liquid and glassy states. It was observed that the local compositions in the Fe72Y6B22 alloy significantly deviate from the compositions of stable crystalline phases, indicating that the Fe72Y6B22 alloy has the best glass-forming ability among the alloys studied. However, Fe72Y6B22 alloy has two flaws in terms of glass-forming ability, i.e. relatively large atomic diffusivity and insufficiently close atomic packing. The best performance in these two aspects is observed in the Fe72.5Y3.5B24 alloy. Thus, the theoretical study predicts that the best glass former for the Fe-Y-B system is within the compositional range of 22-24 at.% B and 3.5-6 at.% Y.