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arXiv · 2004.08579

Variety of scaling behaviors in nanocrystalline plasticity

P. Zhang·O. U. Salman·J. Weiss·L. Truskinovsky
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Abstract

We address the question of why larger, high symmetry crystals are mostly weak, ductile and statistically sub-critical, while smaller crystals with the same symmetry are strong, brittle and super-critical. We link it to another question of why intermittent elasto-plastic deformation of sub-micron crystals features highly unusual size sensitivity of scaling exponents. We use a minimal integer-valued automaton model of crystal plasticity to show that with growing variance of quenched disorder, which can serve in this case as a proxy for increasing size, sub-micron crystals undergo a crossover from spin-glass marginality to criticality characterizing the second order brittle-to-ductile (BD) transition. We argue that this crossover is behind the non-universality of scaling exponents observed in physical and numerical experiments. The non-universality emerges only if the quenched disorder is elastically incompatible and it disappears if the disorder is compatible.

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P. Zhang, O. U. Salman, J. Weiss, L. Truskinovsky. 2020-04-18. Variety of scaling behaviors in nanocrystalline plasticity. https://doi.org/10.1103/physreve.102.023006

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