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conferenceseries
.com
Volume 6
Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212
Ceramics 2018
May 14-15, 2018
May 14-15, 2018 | Rome, Italy
4
th
International Conference and Expo on
Ceramics and Composite Materials
Investigation of anisotropic mechanical properties of textured KSr
2
Nb
5
O
15
ceramics by ab-initio
calculation and nanoindentation
Qian Chen, Min Wang, Liangliang Liu
and
Feng Gao
Northwestern Polytechnical University, China
B
y applying first-principles calculation based on density functional theory (DFT), elastic properties of KSr
2
Nb
5
O
15
(KSN)
crystals were derived, involving elastic constants, Young’s modulus, Poisson’s ratio, bulk modulus and shear modulus,
hardness, and universal anisotropy index. Calculated results show that in the KSN lattice, Nb-O forms relative strong covalent
effect and Nb-O octahedral distortion causes spontaneous polarization in the KSN crystal. To verify the simulated results
experimentally, textured KSN ceramics with highly oriented grains with tetragonal symmetry were fabricated by RTGG
(Reactive Template Grain Growth) method. Nanoindentation was carried out on textured samples in parallel and perpendicular
to the elongated-shape grains oriented to [001] direction. Measured indentation modulus values are in accordance with the
predictions which show an anisotropic ratio of ~10% between the two tested orientations. Predictions of Young’s modulus
revealed a more pronounced anisotropy with a ratio of ~40% between the [100] direction and at a tilt angle of about 45° from
the [001] direction towards the [100].
chenqian910601@sina.comRes. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C1-015