Metallic glasses and bulk metallic glasses are high-strength metallic alloys with an extraordinary high elastic strain of around 2%. These unique mechanical properties are a direct result of the lack of translational symmetry in amorphous alloys. The absence of a conventional structural ordering makes different deformation mechanisms become active: Instead of dislocation operation as in crystals, nanometre-thick shear bands are the carriers of plastic strain in these disordered materials. Unfortunately, the formation of shear bands is based on a shear-softening phenomenon, which generally ends up in catastrophic failure after marginal plastic strains.

Premature failure can be avoided if heterogeneities are introduced into the glass. These inhomogeneities interact with shear bands just being formed or propagating and retard the development of fracture-causing defects (Fig. 1). This way multiple shear bands can be generated and the overall plastic strain increases ^[1].

In our research group at the IKM we develop novel compositions derived from shape memory alloys, which can vitrify upon quenching and which can precipitate shape memory crystals during slower cooling or upon annealing. These particular structural heterogeneities allow to combine the characteristics of the shape memory phase and the glassy phase to get a new response to mechanical loading. Our research efforts specifically concentrate on two different aspects: