New ternary Fe-based bulk metallic glass with high boron content

Abstract

To satisfy thermodynamic and kinetic requirements, Fe-based alloys capable of forming bulk metallic glasses often contain five or more elements. Usually, such compositions are of the type transition-metals/metalloids, with metalloid content around 20 atomic%. Starting from known Fe-based compositions used to make melt-spun glassy ribbons, purifying the master alloy by fluxing with B2O3 and using copper mould casting, a ternary Fe66Nb4B30 bulk metallic glass was obtained. To our knowledge this is the first Fe-based fully amorphous bulk metallic glass with just three atomic constituents. The alloy is ferromagnetic with Curie temperature T c = 646 K, glass transition temperature T g = 845 K, crystallization temperature T x = 876 K, liquidus temperature T liq = 1451 K and having a mechanical strength of 4 GPa.