Rate dependence of grain boundary sliding via time-scaling atomistic simulations

F Hammami and Y Kulkarni, JOURNAL OF APPLIED PHYSICS, 121, 085303 (2017).

DOI: 10.1063/1.4977105

Approaching experimentally relevant strain rates has been a long- standing challenge for molecular dynamics method which captures phenomena typically on the scale of nanoseconds or at strain rates of 10(7) s(-1) and higher. Here, we use grain boundary sliding in nanostructures as a paradigmatic problem to investigate rate dependence using atomistic simulations. We employ a combination of time-scaling computational approaches, including the autonomous basin climbing method, the nudged elastic band method, and kinetic Monte Carlo, to access strain rates ranging from 0.5 s(-1) to 10(7) s(-1). Combined with a standard linear solid model for viscoelastic behavior, our simulations reveal that grain boundary sliding exhibits noticeable rate dependence only below strain rates on the order of 10 s(-1) but is rate independent and consistent with molecular dynamics at higher strain rates.

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