Anelastic strain and structural anisotropy in homogeneously deformed Cu64.5Zr35.5 metallic glass

Using plastic deformation tests and high-energy X-ray scattering, we examined the anelastic strain and structural anisotropy in a binary Cu64.5Zr35.5 metallic glass deformed homogeneously under uniaxial compression at 425 °C, which is approximately 60 °C below the glass transition temperature. For a sample quenched immediately after deformation, we find that the atomic structure observed by X-ray scattering is anisotropic with the average bond length parallel to the loading axis being smaller than that of an undeformed, structurally relaxed reference sample, while the average bond length normal to the loading axis is dilated relative to the same reference sample. For a different sample annealed at 425 °C for 500 s immediately following deformation, the magnitude of the structural anisotropy decreases as anelastic strain is recovered. The relationship between the atomic-scale structural rearrangements that occur during annealing and the macroscopic anelastic strain recovery is discussed.