Paper Titles
Characterization and Optimization of Lygodium Circinnatum (Nito) Fiber Properties through Alkali Treatment and Factorial Design
p.3
Comparative Analysis of the Effective Nonlinear Elastic Modulus of Three Glassy Polymers
p.17
Optical and Structural Microstriation of Sapphire Grown by Different Methods
p.25
Four Types of Magnetic Subsystems in Dilute Magnetic Semiconductors Based on A4B6 and A3B6 Compounds
p.33
Peculiarities of the Mechanical Response of Sapphire under Nanoindentation
p.43
Copper Test Melts with Additions of Pb, Bi, As, Sb and Sn
p.53
A Bronze Button from Late Bronze Age Site of Inzersdorf ob der Traisen
p.61
Roman Bronze Objects from the Archaeological Site of Burg in Burgenland, Austria
p.69
Fresh State Performance of Concrete with Recycled Glass Powder as Cement Replacement and Nanosilica
p.79

Peculiarities of the Mechanical Response of Sapphire under Nanoindentation

Article Preview

Abstract:

The nucleation of dislocations in sapphire of various structural perfection has been investigated by nanoindentation. The studies were carried out on crystallographic planes С(0001), a(1 1 2 0), R (0 112). In the curve of indentation of a Berkovich indenter into the single crystals, an abrupt transition from elastic to plastic deformation has been observed at a depth of about 75 nm due to the nucleation of dislocations in the initially dislocation free region under the contact. Deterioration of structural perfection results in a decrease in shear stresses under which dislocations nucleated. It is shown that the anisotropy of sapphire nanohardness is less pronounced than the static one.

You might also be interested in these eBooks
Metallographic, Functional Materials, Polymers and Composites View Preview

Info:

Periodical:

Materials Science Forum (Volume 1180)

Pages:

43-49

DOI:

https://doi.org/10.4028/p-v8haIT

Citation:

Cite this paper

Online since:

March 2026

Authors:

Aleksandr Voloshyn*, Galina Tolmachova, Elena Dolzhenkova, Pavlo Konevskyi, Leonid Lytvynov

Keywords:

Elastic–Plastic Transition, Nanoindentation, Sapphire, Structural Perfection

Export:

RIS, BibTeX

Price:

Permissions CCC:

Request Permissions

Permissions PLS:

Request Permissions

Сopyright:

© 2026 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

* - Corresponding Author

References

[1] E.R. Dobrovinskaya, L.A. Lytvynov, V.V. Pishchik, Sapphire: material, manufacturing, applications, Springer Science & Business Media, New York, (2009).

DOI: 10.1007/978-0-387-85695-7

Google Scholar

[2] S. N. Dub, N. V. Novikov, Testing of solids for nanohardness, Superhard Mater. 6 (2004) 16-32.

Google Scholar

[3] W.C. Oliver, G.M. Pharr, An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments, J. Mater. Res. 7 (1992) 1564-1583.

DOI: 10.1557/JMR.1992.1564

Google Scholar

[4] S.N. Dub, V.V. Brazhkin, N.V. Novikov, et al., Comparative Studies of Mechanical Properties of Stishovite and Sapphire Single Crystals by Nanoindentation, Superhard Mater. 32 (2010) 406-414.

DOI: 10.3103/S1063457610060067

Google Scholar

[5] S.N. Dub, V.V. Brazhkin, V.A. Belous, G.N. Tolmacheva, P.V. Konevskiy, Comparative Nanoindentation of Single Crystals of Hard and Superhard Oxides, Superhard Mater. 36 (2014) 217-230.

DOI: 10.3103/S1063457614040017

Google Scholar

[6] Oliver WC, Pharr GM. Measurement of hardness and elastic modulus by instrumented indentation: advances in understanding and refinements to methodology. J Mater Res 19 (2004) 3–20.

DOI: 10.1557/jmr.2004.19.1.3

Google Scholar

[7] C.R. Krenn, D. Roundy, M.L. Cohen, D.C. Chrzan, J.W. Morris, Jr., Connecting atomistic and experimental estimates of ideal strength, Phys. Rev. B, 65 (2002) art. 134111.

DOI: 10.1103/PhysRevB.65.134111

Google Scholar

[8] J.Frenkel, Zur Theorie der Elastizitätsgrenze und der Festigkeit kristallinischer Körper, Z. Phys., 37 (1926) 572–609.

DOI: 10.1007/bf01397292

Google Scholar

[9] M. Bhattacharya, A. Dey, A.K. Mukhopadhyay. Influence of loading rate on nanohardness of sapphire. Ceramics International 42 (2016) 13378-13386.

DOI: 10.1016/j.ceramint.2016.05.091

Google Scholar

[10] T. Qiu, F. Jiang, N. Wang, J. Lin, Z. Tian, Y. Wu, Q. Wen, J. Lu. Atomistic understanding of the variable nano-hardness of C-plane sapphire considering the crystal anisotropy. Journal of Materials Research and Technology 29 (2024) 4514-4525.

DOI: 10.1016/j.jmrt.2024.02.161

Google Scholar