The general effect of atomic size misfit on glass formation in conventional and high-entropy alloys

It is a longstanding notion that atomic size misfit plays an important role with regard to glass formation in multi-component alloys. In the previous studies, this atomic size effect was commonly modeled as an “inclusion-in-matrix” problem and glass formation was usually linked to a threshold volume strain in “matrix” or solvent atoms. However, it becomes difficult to directly apply this approach to high entropy alloys, which are in lack of a clear distinction between solvent and solute atoms. With the simple geometric model we recently developed, here we show that glass formation in over two hundred glass-forming alloys, including conventional and high-entropy alloys, can be correlated with the excessive fluctuation in the intrinsic residual strains that result from the atomic size misfit. This interesting behavior suggests that, in most glass-forming multicomponent alloys hitherto reported, the atomic size effect acts with the chemistry effect to promote glass formation. Furthermore, our findings also imply that glass formation in multi-component alloys, regardless of their compositional complexity, may be rationalized with the Lindamann's criterion that was long established for the instability of crystalline lattices.