Shear Transformation Zone Dynamics Modeling of Deformation in Metallic Glasses
A mesoscale shear transformation zone (STZ) dynamics model is presented to investigate the deformation behaviors of metallic glasses that span significant time and length scales. The modeling framework involves coarse-graining STZs, the fundamental deformation unit in metallic glasses, onto a finite element mesh and controlling the stochastic activation of these STZs using the kinetic Monte Carlo algorithm based on the energetics of the glass system. The combination of these two features allows simulating diverse deformation modes of metallic glasses at large time and length scales while providing a microscopic view of the process that dominates the behaviors. The adaption of the STZ dynamics framework to treat complex phenomena is discussed, including a detailed examination of the shear banding process, simulated contact mechanics, and an examination of the interplay of deformation and structural evolution via the incorporation of a free volume state variable. The chapter concludes with the challenges and future development of the STZ dynamics model.
LL was supported by the US Department of Energy, Office of Science, Basic Energy Sciences (BES), by award no. DE-SC0016164. ERH was supported by the National Science Foundation under award no. DMR-1507095.
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