Characterization of structural inhomogeneity in Al88Ce8Co4 metallic glass

Abstract 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.