The material-dependence of plasticity in metallic glasses: An origin from shear band thermology

摘要

The material origin of plasticity in metallic glasses is a puzzled question for decades. In this work, we tackled this question from a perspective of excessive heating. With a simultaneous heat generation and dissipation model to describe the spatial and temporal distribution of temperature-rise in shear bands, an upper bound of temperature-rise of about tens of Kelvins was noticed for the reported stable shear banding. These results implied the fracture of metallic glasses being triggered at some critical temperature-rise. Based on the thermal property data of a series of bulk metallic glasses (BMGs) with different plasticity, a trend of low temperature-rise in large plasticity BMGs was revealed. A new material-dependent parameter based on thermal properties was then suggested to estimate or predict the plasticity in metallic glasses. This study provides a reasonable physical picture to understand the origin of BMGs' fracture and their different plasticity, which sheds a light to the understanding of the complex mechanical properties of these materials.