Structural inhomogeneities in bulk metallic glasses

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The aim of this project is to advance a fundamental understanding of both the structural aspects and the mechanical properties of bulk metallic glasses. It is envisioned that understanding the role of structural inhomogeneities in the process of heterogeneous flow allows to ultimately tailor ductility in bulk metallic glasses. In this project, advanced transmission electron microscopy methods including fluctuation electron microscopy as the main tool to unravel the medium-range order will be combined with X-ray and neutron scattering experiments as well as reverse Monte Carlo simulations. The combination of these state-of-the-art methods including in-situ experiments is expected to lead to a significant leap forward in understanding the intrinsic interrelation between structure and deformation mechanisms of metallic glasses. Especially the approach to liaise systematic experiments with modelling and simulations is expected to improve the picture of how topological and chemical heterogeneities evolve as a function of composition and/ or in the course of deformation and how they in turn govern irreversible deformation in metallic glasses. This challenging research project based on joint preliminary studies will be tackled through concerted efforts and the cross-boarder expertise of the participating groups at the University of Vienna (Austria) and the Leibnitz Institute IFW, Dresden (Germany). In order to analyse this complex matter, the following five crucial goals are identified:i) Role of composition on the short-range and medium-range order of different bulk metallic glasses (BMGs)ii) Influence of the cooling rate on the structure of different BMGs (iii) Effect of mechanical pre-treatment on the structure of different BMGs (iv) Impact of structural relaxation on various length scales of BMGs in different states(v) Modelling of the structure of BMGs by the method of reverse Monte Carlo simulations Our cross-border project is set up to explore cutting-edge aspects in the field of materials science and to deliver a comprehensive picture of the glassy structure. This includes local changes at different length scales caused by thermal or mechanical pre-treatments. Moreover, the expected results are important for establishing principles and routes for the development and design of materials with improved properties and for finally exploiting the full potential of bulk metallic glasses as novel structural material.