Size-Dependent Deformation of Nanocrystalline Pt Nanopillars

Abstract

We report the synthesis, mechanical properties, and deformation mechanisms of polycrystalline, platinum nanocylinders of grain size d = 12 nm. The number of grains across the diameter, D/d, was varied from 5 to 80 and 1.5 to 5 in the experiments and molecular dynamics simulations, respectively. An abrupt weakening is observed at a small D/ d, while the strengths of large nanopillars are similar to bulk. This "smaller is weaker" trend is opposite to the "smaller is stronger" size effect in single crystalline nanostructures. The simulations demonstrate that the size-dependent behavior is associated with the distinct deformation mechanisms operative in interior versus surface grains.

Nanometallic Glasses: Size Reduction Brings Ductility, Surface State Drives Its Extent

“…[10][11][12] Such a discrepancy between the strain based on video frames and that measured in the nanoindenter is typical and likely stems from the effects of machine and grip compliances in both sample types and additional substrate effects in EP samples.…”

Effects of Helium Implantation on the Tensile Properties and Microstructure of Ni73P27 Metallic Glass Nanostructures

“…Consequently, the raw displacement data obtained during testing leads to results with high variability in the elastic modulus, which is an unavoidable characteristic shortcoming of nanomechanical testing [3][4][5] . To obtain more accurate results, instead of using the raw data of the measured displacement signal, frames from the in-situ SEM videos were examined to determine the actual displacement.…”

“…To obtain more accurate results, instead of using the raw data of the measured displacement signal, frames from the in-situ SEM videos were examined to determine the actual displacement. This technique allows for more reliable strain data and has been used successfully in many publications [5][6][7] . The InSEM system (Nanomechanics, Inc.) used has a load resolution of 3 nN and a displacement resolution of 0.0002 nm.…”

Micropillar compression testing of powders

“…Microcompression testing is a powerful tool for characterizing materials that are not amenable to standard macrocompression testing, such as nanocrystalline and nanolaminate thin films [1][2][3][4][5], high pressure torsion specimens [6][7][8][9], and phase-specific tests in multi-phase alloys [10][11][12][13][14]. In this technique, micron-or submicron-scale pillars are compressed in a nanoindenter fitted with a flat punch tip.…”