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Scanning electron microscopy observations of shear steps on Zr-based bulk metallic glasses show direct evidence of shear band melting due to heat generated by elastic energy release. The estimated range of attained temperatures and the observed morphologies are consistent with shear steps forming at a subsonic speed limited by a required redistribution of local microscopic stresses. The calculations indicate that a 0.2μm layer melts in the vicinity of a shear band forming a 1μm shear step. The plastic part of the stress strain curve is serrated but a majority of shear events are not associated to serrations.

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The atomic structure of Zr–Cu binary amorphous alloys was studied using real space pair distribution functions derived from x-ray diffraction. The structure can be modeled by an ideal solution approximation because of relatively weak Cu–Zr atomic interactions. Addition of Al to Zr–Cu metallic glasses modifies the atomic structure in the short and medium range order because of the strongly attractive interaction between Al and Zr atoms. These interactions generate strong deviations from the ideal solution behavior.

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 B 2 O 3 and using copper mould casting, a ternary Fe 66 Nb 4 B 30 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 ¼ 646 K, glass transition temperature T g ¼ 845 K, crystallization temperature T x ¼ 876 K, liquidus temperature T liq ¼ 1451 K and having a mechanical strength of 4 GPa.

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