Pt nanoparticle compression studied with microscopy and atomistic modeling

Interested in how mechanical deformation changes at the nanoscale?

Ingrid Espinosa, Ashlie Martini, and their colleagues at the University of California- Merced and University of Pittsburgh published exciting results obtained using their Hummingbird Scientific in-situ nano-manipulator TEM sample holder to investigate deformation mechanics of nanoscale materials. The study combined experimental in-situ compression under TEM with atomistic modeling.

The precise manipulation of the probe allowed for the compression of small Pt nanoparticles. The holder was modified to include an atomic force microscope (APT) probe, which allowed for sensing of the applied load in the hundreds of nanonewton (nN) range. TEM videos showing in-situ compression of an 11.5 nm Pt nanoparticle were acquired and correspond to load measurements. Experimental values for critical resolved shear stress for failure agreed well with molecular dynamics (MD) simulations of a nanoparticle of similar size, 1.28 and 1.15 GPa respectively for experimental and simulation. The MD provided extra details showing dislocation nucleation and propagation during compression.

Figures showing in-situ TEM video of Pt NP compression showing deformation and slip (top). Applied force vs time for a) experimental and b) MD simulation, c) Frames of in-situ compression (top) corresponding to distinct stages of the simulation (bottom).

This integrated approach demonstrated an exciting new application of @Hummingbird Scientific’s nano-manipulator, where the modified APT probe provides a few 100 nN force, but with nN resolution. This was combined with in-situ TEM enabling direct visualization of morphological evolution at high magnification and comparison to simulation using digital image correlation (DIC).

Reference:  Ingrid M. Padilla Espinosa, Soodabeh Azadehrenjbar, Ruikang Ding, Andrew J. Baker, Tevis D. B. Jacobs, and Ashlie Martini, Applied Physics Letters 120 013101 (2022) DOI: 10.1063/5.0078035 Full paper Copyright © 2022 American Institute of Physics

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