Shaping of metallic glasses by stress-annealing without thermal embrittlement

Thermomechanical shaping of metallic glasses has previously been reported to result in severe thermal embrittlement. This phenomenon is most likely the reason why little effort has been made to exploit the mechanical properties of complex shapes attainable by thermomechanical shaping of metallic glass tapes and ribbons. The present study revealed time–temperature windows in which metallic glasses can be shaped by thermal annealing while remaining fully ductile. These include binary (Fe83B17, Co80B20 and Pd82Si18), ternary (Fe81.5B14.5Si4 and Cu60Zr30Al10) and more complex quaternary Zr70Ni16Cu6Al8 glassy alloys of both metal–metalloid and metal–metal types. All showed full bending ductility after shaping. The thermomechanical processing leading to full shaping without thermal embrittlement was successfully modeled using the approach of A.I. Taub (Acta Metallurgica 1981) based on the free-volume model of structural relaxation. The results are of direct interest for applications of metallic glasses as springs.

► Metallic glasses can be thermo-mechanically shaped.
► Six of seven tested metallic glasses are full ductility after shaping.
► Shaping of these metallic glasses into springs was successfully tested.