Fractographic details of directly cast amorphous and nanocrystalline alloy wire

The fracture surfaces of metallic glass wire and nanocrystalline wire were examined by scanning electron microscopy. Metallic glass wire failed in tension under ultra high stress and the surface morphology consists of a smooth and a veined region, evident of failure initiated by a shear mechanism followed by localized melting in the vicinity of the shear. Fracture morphologies of the nanocrystalline wire and glassy wire fractured in bend fatigue reveal features similar to those of classical brittle failure in glasses, showing features of mirror, mist, hackle and branching pattern. The dimensions of these patterns were used to estimate fracture properties of the wire samples