The relationship between shear bands and deformability in bulk metallic glasses

Abstract

It has been well documented that the plastic deformation of bulk metallic glasses (BMGs) is localized in narrow shear bands, resulting in rapid propagation of these shear bands and catastrophic failures of BMGs subjected to loads. Shear bands in BMGs play a dominant role in their deformation behavior and macroscopic properties. In order to comprehensively understand the deformation mechanism of BMGs, it is necessary to investigate the formation of shear bands and consequent deformation. In present paper, Zr62.55Cu17.55Ni9.9Al10 and Zr64.80Cu14.85Ni10.35Al10 BMGs were prepared and the effect of indentation on the formation of shear bands was studied at room temperature. The results showed that Zr62.55Cu17.55Ni9.9Al10 BMG deforms through formation of radiation-like and circular shear bands, while for Zr64.80Cu14.85Ni10.35Al10 BMG, basically only radiation-like shear bands can be found after indentation deformation. The density of shear bands in the former is larger than that in the latter with a same loading condition. The different indentation deformation behavior in the two BMGs might be attributed to the differences in thermodynamic stabilities and intrinsic natures. The formation mechanism of the shear bands as well as the deformation mechanism of the BMGs were analyzed and discussed.