Plasticity in bulk metallic glasses investigated via the strain distribution

Abstract

We measured the atomic-scale elastic strain in order to investigate the yielding of ${\mathrm{Zr}}_{55}{\mathrm{Cu}}_{20}{\mathrm{Ni}}_{10}{\mathrm{Al}}_{10}{\mathrm{Ti}}_{5}$ and ${\mathrm{Cu}}_{47.5}{\mathrm{Zr}}_{47.5}{\mathrm{Al}}_{5}$ bulk metallic glasses (BMGs) by x-ray synchrotron radiation at room temperature. High resolution strain scanning reveals a deviation from the linear stress-strain relationship at the onset of macroplastic flow. Similar to polycrystalline metals, a saturation of the elastic strain components has been revealed in the case of the ``plastic'' ${\mathrm{Cu}}_{47.5}{\mathrm{Zr}}_{47.5}{\mathrm{Al}}_{5}$ BMG. The results show that the atomic-level elastic strains of the plastic ${\mathrm{Cu}}_{47.5}{\mathrm{Zr}}_{47.5}{\mathrm{Al}}_{5}$ BMG are more homogeneous compared to the ``brittle'' ${\mathrm{Zr}}_{55}{\mathrm{Cu}}_{20}{\mathrm{Ni}}_{10}{\mathrm{Al}}_{10}{\mathrm{Ti}}_{5}$ glass.