Mechanical properties and dislocation nucleation in nanocrystals with blunt edges
J Amodeo and K Lizoul, MATERIALS & DESIGN, 135, 223-231 (2017).
The deformation of blunt nanocrystals under uniaxial compression is modelled using molecular dynamics simulations. Ni3Al blunt nanoparticles are built using a simple algorithm that allows continuous shape design from perfectly-sharp nanocubes to nanospheres including a large set of cuboid shapes. Simulation results show that blunt nanoparticles are significantly stronger in comparison to their perfectly cubic counterparts and deform due to the nucleation of partial dislocations and deformation twins. Furthermore, while the early plastic deformation of nano-objects is generally attributed to the nucleation of dislocations from the surface, here we show that homogeneous dislocation nucleation may also happen in blunt nanoparticles and a size-dependent transition parameter is defined. This study emphasizes how much the design of virtual samples is crucial when modeling nano-objects mechanical properties using molecular dynamics simulations and provides new insights onto potential incipient plasticity features at the nanoscale. (C) 2017 Elsevier Ltd. All rights reserved.
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