Characterization of structural inhomogeneity in Al₈₈Ce₈Co₄ metallic glass

Structural inhomogeneity is found to be a promising way to overcome intrinsic brittleness and to improve the plasticity of metallic glasses (MGs), although such inhomogeneity has not been well-understood. In this study, quantitative observations and theoretical explanations on the structural inhomogeneity were presented for Al₈₈Ce₈Co₄ MG. Applying a technique called energy filtered electron diffraction (EFED), different medium-range orders (MROs) reflected from conspicuous and inconspicuous prepeaks, were observed, which, following reduced pair distribution functions obtained from the EFED measurement, correspond to different short-range orders (SROs). Then using reverse Monte Carlo (RMC) simulation, the structural inhomogeneity is attributed to diversity of Al-Co clusters, which lead to loosely and densely packed local atomic structures and contribute to soft and hard regions, as evidenced by synchrotron radiation X-ray diffraction, dynamic mechanical analysis and nano-indentation. The obtained structural essence of intrinsic inhomogeneity in MGs lays the foundation for further understanding and designing MGs with high plasticity, by adjusting properly inhomogeneous structure.