Comparative studies of mechanical properties of stishovite and sapphire single crystals by nanoindentation
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Comparative nanoindentation tests of stishovite and sapphire single crystals have been performed. It has been found that nanohardness of the (0001) plane of sapphire at a depth of 200 nm is 29.1 ± 0.1 GPa, while the nanohardness of the (110) plane of stishovite is 38.1 ± 0.6 GPa, the tests conditions being the same. The specifics of elastoplastic transition in sapphire and stishovite single crystals and alumina-based polycrystalline ceramic when plastic deformation is localized in a submicron region have been studied. Anomalous elastoplastic transition in stishovite has been revealed. A possibility that anomalous mechanical behavior of stishovite at the nanoscale may be due to a strong softening of the lattice as a precursor of the formation of a post-stishovite phase of silica with the CaCl2 structure in an indent has been discussed.
Key wordsnanoindentation nanohardness elasto-plastic transition sapphire stishovite
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- 1.Stishov, S.M. and Popova, S.V., A New Dense Modification of Silica, Geokhimiya, 1961, vol. 10, pp. 923–926.Google Scholar
- 6.Golovin, Yu.V., Nanoindentipovanie i ego vozmozhnosti (Nanoindentation and Its Potentialities), Moscow: Mashinostroenie, 2009.Google Scholar
- 11.Dub, S.N., Lim, Y.Y., and Chaudhri, M.M., Nanohardness of High Purity Cu (111) Single Crystals: the Effect of Indenter Load and Prior Plastic Sample Strain, J. Appl. Phys., 2010, vol. 107, art. 4043510.Google Scholar
- 16.Golovin, Yu.I. and Dub, S.N., A Spasmodic Transition from Elastic to Elastoplastic Deformation at the Initial Stage of Nanoindentation, Doklady Russian Ac. Sci., 2003, vol. 393, no. 2, pp. 180–183.Google Scholar
- 17.Galin, L.A., Three-Dimensional Contact Problems of the Elasticity Theory for Dies of a Circular Shape in Plane, Prikladnaya Matematika i Mekhanika, 1946, vol. 10, no. 4, pp. 425–448.Google Scholar
- 19.Johnson, K.L., Contact Mechanics, Cambridge: Cambridge University Press, 1985.Google Scholar
- 22.Shieh, S.R. and Duffy, T.S., Strength and Elasticity of SiO2 across the Stishovite-CaCl2-Type Structural Phase Boundary, Phys. Rev. Lett., 2002, vol. 89, no. 25, art. 255507.Google Scholar
- 24.Gogotsi, Y.G., Domnich, V., Dub, S.N., et al., Cyclic Nanoindentation and Raman Micro-Spectroscopy Study of Phase Transformations in Semiconductors, J. Mater. Res., 2000, vol. 15, no. 3, pp. 871–879.Google Scholar