Strain dependence of peak widths of reciprocal- and real-space distribution functions of metallic glasses from in situ x-ray scattering and molecular dynamics simulations

摘要

We have examined the relationship between the vanance in the atomic-level hydrostatic pressure, <△p~2>~(1/2), and the widths of the first peaks in the reciprocal- and real-space distribution functions for elastically deformed metallic glasses. In situ synchrotron x-ray scattering studies performed on a binary Cu_(64.5)Zr_(35.5) glass subject to uniaxial loading reveal that the width of the first peak in the reduced-pair distribution function is dependent on the different elastic responses of the partial-pair correlations. Molecular dynamics (MD) simulations of the same binary glass, as well as a single-component glass, subject to hydrostatic deformation show that the widths of the first peaks in the partial-pair distribution functions are affected by length-scale-dependent changes in the relative atomic separation in the first nearest-neighbor shell. Moreover, the MD simulations show that the strain dependencies of the partial-pair peak widths do not necessarily match the strain-dependence of <△p~2>~(1/2), The results suggest that the widths of the peaks in the reciprocal- and real-space functions are not solely dependent on <△p~2>~(1/2) but rather are also affected by the atomic rearrangements associated with elastic deformation.