Examining crystallographic orientation dependence of hardness of silica stishovite

Luo, Sheng-Nian, Swadener, J.G., Ma, Chi and Tschauner, Oliver (2007). Examining crystallographic orientation dependence of hardness of silica stishovite. Physica B: Condensed Matter, 399 (2), pp. 138-142.

Abstract

We conducted nanoindentation to explore the hardness and elastic properties of silica stishovite, synthesized at high pressure and quenched to ambient conditions. A total of 10 crystallographic orientations were examined on selected grains with a maximum load of 4 or 20 mN. We observed discontinuity in the load-displacement curve (pop-in) for the [2 5 over(1, -)] and [6 2 over(1, -)] grains subjected to a maximum load of 20 mN. The single-crystal hardness at high plastic deformation is quasi-isotropic with an average of 32 ± 1 GPa, similar to the polycrystalline hardness reported earlier; the theoretical hardness determined from the experiments is about 54 ± 3 GPa. These two hardnesses suggest that stishovite is one of the hardest oxides. The measured indentation moduli are close to the predictions at low load (minor plasticity) but are considerably lower at high load (high plasticity). Both indentation hardness and modulus decrease with increasing plasticity. Our results underscore the necessity of considering the degree of plastic deformation when interpreting hardness and elastic moduli from indentation experiments.

Publication DOI: https://doi.org/10.1016/j.physb.2007.06.011
Divisions: Engineering & Applied Sciences > Mechanical Engineering & Design
Engineering & Applied Sciences
Additional Information: Copyright 2008 Elsevier B.V., All rights reserved.
Uncontrolled Keywords: silica stishovite ,nanoindentation ,hardness ,elastic modulus
Full Text Link: https://www.its ... _stishovite.pdf
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
Published Date: 2007-11-01
Authors: Luo, Sheng-Nian
Swadener, J.G. ( 0000-0001-5493-3461)
Ma, Chi
Tschauner, Oliver

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