Investigation of the relationship between primary and secondary shear bands induced by indentation in bulk metallic glasses
The paper develops an analytical model capable to predict the positions both of primary shear band (PSB) and of secondary shear band (SSB) circles formed in Vickers indentations of bulk metallic Zr-based bulk metallic glasses (BMG). The analytical model is based on the force balance for an arbitrary PSB annulus and Johnson's cavity model in contact mechanics. It is shown that the ratio of the \(n\)-th shear band radius to the half-diagonal contact length is a constant factor, which depends on the material properties, when the specimen starts to yield and form a shear band circle. At the same time, the radius of the SSB circles is \(\sqrt2\) times as large as that of the PSB circle. In order to investigate the SSB circle, the Tresca criterion is used together with the assumption that the SSB circles form right angle at the two intersection points. The presented experimental results show a good agreement with the two kinds of shear band circles. The obtained results also show that the radius ratio of any two adjacent PSB circles is approximately a constant value. Moreover, it is shown that the formation of shear bands in the Zr-based BMG is dominated rather by cracking than by crystallization. The present model can be applied to predict the shear band behavior precisely if the radius of the PSB circle is evaluated on the basis of a stationary origin point.
scientific article; zbMATH DE number 5994159
scientific article