OsCo-based high-temperature bulk metallic glasses with robust mechanical properties

A family of novel Os-Co-Ta-B high-temperature bulk metallic glasses (HTBMGs) was fabricated by introducing high-modulus refractory metal Os (50 wt% at least) and strong-covalent metalloid B (up to 40 at%). These OsCo-based HTBMGs exhibit high glass transition temperature up to 1028 K and high Vickers microhardness up to 17.6 GPa. The compressive strength can reach up to 6.0 GPa at room temperature and even over 4 GPa at 873 K (a new record for strength of metallic materials at this high temperature so far). The impressive strength is attributed to the strong bond characteristics especially for Ta-Os and B-B bonds. By combining experimental and theoretical analysis for the relationships among alloy composition, atomic structure and the related properties, a promising route was provided to design HTBMGs with desirable properties. The castable OsCo-based HTBMGs with superior mechanical properties and high thermal stabilities are significant for high-temperature applications as advanced structural materials.