Effect of alloying elements with positive heat of mixing on the free volume and compressive plasticity in zrcocual bulk metallic glasses

In this work the effect of alloying an element with positive heat of mixing with Co on the free volume and compressive plasticity of a ZrCoAl bulk metallic glass was investigated. By substituting Co with Cu fully amorphous rods of 2 mm diameter can be obtained over a wide composition range. With the addition of Cu the free volume changes from 0.09 to 0.18% and the fracture plastic strain changes from 1 to 12.4%. However there is no strong correlation between the free volume and the compressive plasticity. In addition to the free volume content other factors such as the size shape and distribution of the free volume sites may also affect the plasticity of BMGs.