Metallic glasses fracture

Fig. 13. Transition between ductile fracture and brittle fracture when Al QFe Gd metallic glass is aimealed at 170°C.

Slides Plastic cavitation around inclusions in metals (e.g. metallographic section through neck in tensile specimen) SEM pictures of fracture surfaces in ductile metals, glass, alkali halide crystals. 

The fracture of metallic glasses occurs by the formation of shear bands having a 45 orientaiion relutive to the tensile axis. Typical veining uti the fracture surface is a characteristic of almost all metallic glasses. 

The deleterious embrittlement of a glassy metal during annealing is also accompanied by a change in fracture mode. Almost all metallic glasses containing Fe, Co. and Al show this behavior... 

Fracture of wires Fracture of metallic glasses Deformation texture Drawing defects Polycrystalline strengthening Fatigue of micro-wires Fatigue of metallic glasses Bonding wires... 

Li. J.C.M. (1978) Micromechanisms of Deformation and Fracture. In Metallic Glasses, American Society for Metals, Metals Park, OH. 

Metallic Glasses. Electrically conducting glasses can be prepared from combinations of predominantly metallic elements by rapid cooling or vapour deposition. Their magnetic properties make them suitable for low-loss transformer cures, and their mechanical strengths approach theoretical fracture strength, as local dislocation fracture mechanisms do not operate. 

Figure 9-12. Left field fracture of a gold-plated iron-nickel-cobalt alloy. Fracture occurred at the metal/glass interface (arrow points to fracture). Right stress-corrosion cracking in an iron-nickel-cobalt alloy. Both transgranular and intergranular cracks are observed (arrows).

This review deals mainly with metals. The literature on their SCC is immense, and there are many useful texts and conference proceedings [1-12]. A brief history was published by Newman and Procter [13] and should be consulted for further historical details, especially the metal-environment combinations known to exhibit SCC. Plasticity plays a key role in SCC of metals, in contrast to inorganic glasses and ceramics, which are brittle solids and crack via reaction of the corrodent with highly stressed bonds at an atomically sharp crack tip [14]. Metal-induced fracture [15], formerly called hquid-metal embrittlement, remains a tantalizing phenomenon and... 

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