Pressure-induced stiffness of Au nanoparticles to 71 GPa under quasi-hydrostatic loading

Xinguo Hong, Thomas S. Duffy, Lars Ehm, Donald J. Weidner

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The compressibility of nanocrystalline gold (n-Au, 20 nm) has been studied by x-ray total scattering using high-energy monochromatic x-rays in the diamond anvil cell under quasi-hydrostatic conditions up to 71 GPa. The bulk modulus, K 0, of the n-Au obtained from fitting to a Vinet equation of state is ∼196(3) GPa, which is about 17% higher than for the corresponding bulk materials (K 0: 167 GPa). At low pressures (<7 GPa), the compression behavior of n-Au shows little difference from that of bulk Au. With increasing pressure, the compressive behavior of n-Au gradually deviates from the equation of state (EOS) of bulk gold. Analysis of the pair distribution function, peak broadening and Rietveld refinement reveals that the microstructure of n-Au is nearly a single-grain/domain at ambient conditions, but undergoes substantial pressure-induced reduction in grain size until 10 GPa. The results indicate that the nature of the internal microstructure in n-Au is associated with the observed EOS difference from bulk Au at high pressure. Full-pattern analysis confirms that significant changes in grain size, stacking faults, grain orientation and texture occur in n-Au at high pressure. We have observed direct experimental evidence of a transition in compressional mechanism for n-Au at ∼20 GPa, i.e. from a deformation dominated by nucleation and motion of lattice dislocations (dislocation-mediated) to a prominent grain boundary mediated response to external pressure. The internal microstructure inside the nanoparticle (nanocrystallinity) plays a critical role for the macro-mechanical properties of nano-Au.

Original languageEnglish (US)
Article number485303
JournalJournal of Physics Condensed Matter
Volume27
Issue number48
DOIs
StatePublished - Nov 16 2015

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics

Keywords

  • high pressure DAC
  • nano materials
  • x-ray diffraction

Fingerprint Dive into the research topics of 'Pressure-induced stiffness of Au nanoparticles to 71 GPa under quasi-hydrostatic loading'. Together they form a unique fingerprint.

  • Cite this