Processing routes, microstructure and mechanical properties of metallic glasses and their composites

Metallic glasses represent an interesting group of materials as they are superior in certain mechanical properties, i.e. they reach near theoretical strength, exhibit large elastic strain (2%) and low elastic modulus compared to their crystalline counterparts. The discovery of new alloy compositions solidifying to bulk glassy samples allows for conventional mechanical characterization and raises the hope for possible applications as structural material. In order to improve and tailor the mechanical properties, composite materials have been developed that consist of a glassy matrix with second phase dispersions of different chemical compositions, morphology, and different length scale. This article reviews the different processing routes, the evolution of different microstructures and the resulting elastic and plastic properties of metallic glasses and their composites. Additionally, the recently reported monolithic ductile bulk metallic glasses will be discussed in terms of their structure, chemical composition and their unique "work hardening "-like behavior.