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

摘要

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. (C) 2016 Elsevier Ltd. All rights reserved.