软-硬两相结构异质性对非晶合金剪切带传播机制的影响研究

Effect of structural heterogeneity on the shear-band propagation mechanism in soft-hard dual-phase metallic glasses

本文采用分子动力学模拟的方法,研究了具有软-硬两相结构异质性的非晶合金在拉伸变形过程中剪切带的传播机制.发现剪切带由软相区向硬相区传播时,会在界面处发生停滞并在随后的传播过程中发生剪切路径的改变.这种结构的差异性使软硬两相发生不同步的屈服行为,导致剪切带的不连续传播行为.此外,发现硬相区中的微观结构的不均匀性导致应力和局部熵的不均匀分布,剪切变形区域会选择在大局部应力和高局部熵的区域发生.本工作不仅加深了对剪切带在软-硬两相结构异质性非晶合金中传播机制和行为的认识,并对设计开发具有更优力学性能的非晶合金材料具有启发作用.

In this paper,the shear band propagation mechanism in the soft-hard heterogeneous metallic glass during tensile deformation is investigated using molecular dynamics simulations.Upon percolating from the soft phase to the hard phase,the shear band will stagnate at the interface between these two phases and alter its propagation direction during subsequent shearing.The structural difference leads to the asynchronous yielding of the soft-hard two phases and consequently causes the discontinuous propagation of the shear band.Furthermore,the inhomogeneous nature of the microstructure in the hard phase gave rise to stress and local entropy heterogeneity,resulting in the predilection of shearing in the areas of high stress and high local entropy.This work deepens the understanding of the shear band propagation mechanism in heterogeneous metallic glasses and provides a foundation for designing high-performance amorphous alloys.