Tension-compression asymmetry and twin boundaries spacings effects in polycrystalline Ni nanowires

F Zhang and JQ Zhou, JOURNAL OF APPLIED PHYSICS, 120, 044303 (2016).

DOI: 10.1063/1.4959206

Tension-compression asymmetry could be a notable feature in many nanocrystalline (NC) materials. The scientific and practical research on the tension-compression asymmetry may play an important role of improving the mechanical behavior of NC materials. Using large-scale molecular dynamics (MD) simulations at the strain rate of 10 9 s(-1), both tension and compression tests are complemented in twin-structural polycrystalline Ni nanowires (NWs). The MD simulation suggests that twin boundaries spacing (TBS) has an interesting effect on the tension- compression asymmetry. For NW (radius = 9 nm) with different TBSs, the flow stresses are totally higher under compression than under tension. The asymmetry gets a minimum value at a particular TBS. Such results can be explained by the interplay of the work of dislocations mechanism under various TBSs and the free surface in NWs. Published by AIP Publishing.

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