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Description
Chandra Sekhar Meduri1 Golden Kumar1

1, Texas Tech University, Lubbock, Texas, United States

Bulk metallic glasses (BMGs) deform plastically through localized shear bands at room temperature. It is well established that shear banding process in BMGs depends on multiple parameters such as, the elastic constants, the sample size and processing, and the testing conditions (temperature, strain-rate, and loading geometry). Studying the effects of these variables and linking them to a unifying flow model is critical for fundamental understanding and potential applications of BMGs. In this work, we study the effects of testing temperature and sample size on nucleation and propagation of shear bands and the fracture surface through bending and tensile testing. Bending experiments show an increase in number of shear bands and plasticity with decreasing temperature. Analysis of fracture morphologies from the high-throughput tensile tests show an increasing contribution of thermal softening (through shear offset) and decreasing contribution of defect development (through coalescence of nanovoids and formation of microcracks) to the final fracture as sample size and/or temperature decreases. The results are discussed in terms of existing models for shear band formation and fracture of BMGs.

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