Shear Bands in Monolithic Metallic Glasses: Experiment, Theory, and Modeling

Hubek R, Hilke S, A. Davani F., Golkia M, Shrivastav GP, Divinski SV, Rösner H, Horbach J, and Wilde G

Research article (journal)

Abstract

For applications, metallic glasses need to retain their high strength over enhanced strainranges. However, many metallic glasses show catastrophic failure, even in or close to theend of the regime that conventionally has been thought to be elastic. Recent observationsof irreversible events at low strains shed some doubt on this nomenclature. In fact, theseobservations indicate that although the macroscopic response indicates elastic behavior,the microscopic processes might at least partially be irreversible and time-dependent. Inthat respect, shear bands as the result of shear localization and as the cause of shearsoftening play a decisive role with respect to the performance of metallic glasses undermechanical load. Therefore, in this work, we are aiming at understanding the correlationsbetween glass structure, glass properties and the thermomechanical history of the glassincluding the shear bands on one hand and the plastic yielding on the other hand.Various attempts have been made to explain or model the response of metallic glassesto externally applied shear stresses. Hypotheses have been put forward concerning theimpact of materials parameters or structural aspects that might favor homogeneousplastic flow. Additionally, scenarios have been suggested for the early stages of anelasticand plastic deformation as well as for the transition to localization and shear bandformation/activation. In this contribution, we present a focused viewpoint both fromtheory and modeling as well as an experimental perspective set on the structure andproperties of glasses under shear, with a special focus on shear banding.We also discussthe impact of the local structure of glasses (that depend on the synthesis and processingpath-way) in terms of their medium range order. The impact of chemical composition(including microalloying effects) on kinetic properties of shear bands and elasto-plasticproperties (Poisson’s ratio and three-point bending) is evaluated. These aspects haveseen relatively sparse coverage, but are of far-reaching consequences concerning theproperties of glasses under mechanical stress. Moreover, these aspects can reveal newinsight into the underlying dominant mechanisms and, equally important, allow also toinfer about the early stages of strain localization and to analyze the impact of structuralheterogeneity or processing conditions on plastic yielding.

Details zur Publikation

Release year: 2020
Language in which the publication is written: English