Nucleation of dislocations and twins in fcc nanocrystals: Dynamics of structural transformations

AV Korchuganov and AN Tyumentsev and KP Zolnikov and IY Litovchenko and DS Kryzhevich and E Gutmanas and SX Li and ZG Wang and SG Psakhie, JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 35, 201-206 (2019).

DOI: 10.1016/j.jmst.2018.09.025

This paper reports on a molecular dynamics study of structural rearrangements in a copper nanocrystal during nucleation of plastic deformation under uniaxial tension. The study shows that the resulting nucleation of partial dislocations on the free surface and their glide occurs through local fcc -> bcc -> hcp transformations via consistent atomic displacements. We propose an atomic model for the generation of dislocations and twins based on local reversible fcc -> bcc -> fcc transformations, with the reverse one proceeding through an alternative system. The model gives an insight into possible causes and mechanisms of the generation of partial dislocations and mechanical twins in two and more adjacent planes of plastically deformed nanocrystals. The obtained data allow a better understanding of how plasticity is generated in nanostructured materials. (C) 2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

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