Local structures of two metallic glasses with good plasticity

Abstract

The local structures of two metallic glasses with good plasticity, i.e., Al89La6Ni5 and Cu49Hf 42Al9, were studied by reduced density functions (RDFs) from electron diffraction in a transmission electron microscope. Atomic models were refined against the RDF data using the reverse Monte Carlo (RMC) method and density functional theory (DFT) calculations. This approach allows the contributions of different bond types to the total G(r) to be examined. For Al89La6Ni5, RDFs from different local areas showed three distinct amorphous structures while RDFs from different local areas in Cu49Hf42Al9 were identical, but with a broad spread of Hf-Hf bond lengths. The coexistence of three distinct amorphous states in Al89La6Ni5 and the wide variation of Hf-Hf first neighbour distances in Cu49Hf42Al9 could be associated with the high plasticity for both glasses. © 2010 IOP Publishing Ltd.