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

Journal Article · Mon Nov 16 04:00:00 EST 2015 · Journal of Physics. Condensed Matter

DOI:https://doi.org/10.1088/0953-8984/27/48/485303· OSTI ID:1354493

Hong, Xinguo ^[1]; Duffy, Thomas S. ^[2]; Ehm, Lars ^[3]; Weidner, Donald J. ^[1]

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1. Stony Brook Univ., NY (United States). Mineral Physics Inst.
2. Princeton Univ., NJ (United States). Dept. of Geosciences
3. Stony Brook Univ., NY (United States). Mineral Physics Inst.; Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Directorate

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. In conclusion, the internal microstructure inside the nanoparticle (nanocrystallinity) plays a critical role for the macro-mechanical properties of nano-Au.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
• DOE Contract Number: SC0012704; AC02-98CH10886
• OSTI ID: 1354493
• Report Number(s): BNL--113010-2016-JA
• Journal Information: Journal of Physics. Condensed Matter, Journal Name: Journal of Physics. Condensed Matter Journal Issue: 48 Vol. 27; ISSN 0953-8984
• Publisher: IOP Publishing
• Country of Publication: United States
• Language: English

Related Subjects

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nano materials
x-ray diffraction