Anisotropy of Microhardness and Fracture of Langasite Crystal and Its Structural Basis

The anisotropy of microhardness and fracture of the (0001) basal plane of langasite crystal has been studied using Berkovich indentation under a load of 100 g at different indenter positions. The formation of “crystallographic” microcracks (straight-line and emerging exactly from the impression angl...

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Bibliographic Details
Published inCrystallography reports Vol. 66; no. 6; pp. 1045 - 1050
Main Authors Sizova, N. L., Golovina, T. G., Konstantinova, A. F., Dudka, A. P.
Format Journal Article
LanguageEnglish
Published Moscow Pleiades Publishing 01.11.2021
Springer Nature B.V
Subjects
Anisotropy
Basal plane
Cations
Chemical composition
Crystal structure
Crystallography
Crystallography and Scattering Methods
Crystals
Fractures
Indentation
Microcracks
Microhardness
Modulus of elasticity
Occupancy
Physical Properties of Crystals
Physics
Physics and Astronomy
Structural models
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Summary:The anisotropy of microhardness and fracture of the (0001) basal plane of langasite crystal has been studied using Berkovich indentation under a load of 100 g at different indenter positions. The formation of “crystallographic” microcracks (straight-line and emerging exactly from the impression angles), which propagate in six directions, spaced by 60°, is observed. It is suggested that the observed specific features of microcrack formation are based structurally on the presence of a mixed cation site. As follows from the structural model of a multicell, fractures propagate along the direction of polyhedra with mixed cation occupancy, and the fracture line pushes apart unit cells of different chemical compositions. The Young’s modulus of langasite crystal has been calculated for different crystallographic planes.
ISSN:1063-7745
1562-689X
DOI:10.1134/S1063774521060341