Atomistic simulations are performed to probe the anisotropic deformation inthe compressions of face-centred-cubic metallic nanoparticles. In the elasticregime, the compressive load-depth behaviors can be characterized by theclassical Hertzian model or flat punch model, depending on the surfaceconfiguration beneath indenter. On the onset of plasticity, atomic-scalesurface steps serve as the source of heterogeneous dislocation in nanoparticle,which is distinct from indenting bulk materials. Under [111] compression, thegliding of jogged dislocation takes over the dominant plastic deformation. Theplasticity is governed by nucleation and exhaustion of extended dislocationribbons in [110] compression. Twin boundary migration mainly sustain theplastic deformation under [112] compression. This study is helpful to extractthe mechanical properties of metallic nanoparticles and understand theiranisotropic deformation behaviors.
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