Orientation-dependent deformation mechanisms of bcc niobium nanoparticles

TL;DR

This study uses atomic simulations to explore how bcc niobium nanoparticles deform differently depending on their orientation, revealing distinct elastic and plastic mechanisms that differ from bulk materials.

Contribution

It provides new insights into orientation-dependent deformation mechanisms of bcc nanoparticles, highlighting differences from bulk crystal behavior.

Findings

Surface morphology influences initial elastic response.

Different contact models apply to various orientations.

Distinct dislocation and twinning mechanisms are observed.

Abstract

Nanoparticles usually exhibit pronounced anisotropic properties, and a close insight into the atomic-scale deformation mechanisms is of great interest. In present study, atomic simulations are conducted to analyze the compression of bcc nanoparticles, and orientation-dependent features are addressed. It is revealed that surface morphology under indenter predominantly governs the initial elastic response. The loading curve follows the flat punch contact model in [110] compression, while it obeys the Hertzian contact model in [111] and [001] compressions. In plastic deformation regime, full dislocation gliding is dominated in [110] compression, while deformation twinning is prominent in [111] compression, and these two mechanisms coexist in [001] compression. Such deformation mechanisms are distinct from those in bulk crystals under nanoindentation and nanopillars under compression, and the major differences are also illuminated. Our results provide an atomic perspective on the mechanical behaviors of bcc nanoparticles and are helpful for the design of nanoparticle-based components and systems.