Effects of copper nanoparticle inclusions on pressure-induced fluid- polynanocrystalline structural transitions in krypton
Z Chen and S Jiang and TD Sewell and Y Gan and SY Oloriegbe and DL Thompson, JOURNAL OF APPLIED PHYSICS, 116, 233506 (2014).
The dependence of nanoscale crystal formation from a noble element fluid on the rate of hydrodynamic compression was explored using molecular dynamics. Results were obtained for pure krypton samples as well as ones containing a cubic-or spherical-shaped fcc copper nanocrystal inclusion for compression rates of 1, 10, and 20 MPa/ps. In the absence of Cu, Kr crystals nucleate with apparently random locations and orientations in the sample; slower compression leads to larger nanocrystal size. The effect of the Cu inclusion is to partially mediate the location, orientation, and size of the formed crystals. The effect is larger for the slower compression rate and when the inclusion is cubic rather than spherical in shape. For sufficiently slow compression, the stress state in the cubic Cu inclusion changes from hydrostatic to non-hydrostatic as a consequence of the formation of extended orthotropic hcp/fcc nanostructures in the Kr. The mechanism of the dynamic stress-induced nanostructural transition is explained qualitatively in terms of known geometric effects on the quasi-static indentation response of crystalline materials. (C) 2014 AIP Publishing LLC.
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