Influence of surface atomic structure on the mechanical response of aluminum nanospheres under compression

- Compressed Al nanospheres plastically deform by dislocation nucleation.
- These dislocations are Shockley partials forming at surface contact edges.
- The contact surface structure controls the plasticity, not the nanoparticle size.
- Models available in literature are not applicable.

Molecular Dynamic simulations have been performed to study the mechanical behavior of 〈100〉 oriented aluminum nanospheres under compression, and the influence of size on plasticity mechanisms and yield stress. Plasticity always started by the nucleation of partial dislocations from the surface contact edges. For large enough nanoparticles, the formation of pyramidal structures is observed in a pseudo-elastic regime. The pyramid apex favors dislocation nucleation at high compression levels. The plasticity mechanisms and the yield stress do not depend on nanoparticle size. Instead, our results suggest that the geometry and atomic structure of the layers in contact with the indenters control the plastic deformation.

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