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Temperature dependence of indentation size effect, dislocation pile‐ups, and lattice friction in (001) strontium titanate

Javaid, Farhan and Johanns, K. E. and Patterson, Eric A. and Durst, Karsten (2018):
Temperature dependence of indentation size effect, dislocation pile‐ups, and lattice friction in (001) strontium titanate.
In: Journal of the American Ceramic Society, Wiley, pp. 356-364, 101, (1), ISSN 00027820, [Article]

Abstract

Nanoindentations with a Berkovich type indenter were performed on (001) strontium titanate (STO) single crystal at 25 degrees C and 350 degrees C, analyzing the influence of temperature on the indentation size effect (ISE) and dislocation structure around the residual impression. It is found that the STO exhibits an ISE, which is strongly reduced at 350 degrees C compared to 25 degrees C. The dislocation structure around the residual impression has been resolved using an etch-pit technique. At 25 degrees C, the extension of the dislocation pile-ups were found to be shorter as compared to 350 degrees C. This also correlates with the smaller size effects at 350 degrees C. Peach-Koehler forces and the elastic-plastic indentation stress field were used to model the influence of the lattice frictional stress on the dislocation pile-ups. Based on an equilibrium position of the outermost dislocations, the average lattice frictional stresses were calculated to be 89 MPa and 46 MPa at 25 degrees C and 350 degrees C, respectively.

Item Type: Article
Erschienen: 2018
Creators: Javaid, Farhan and Johanns, K. E. and Patterson, Eric A. and Durst, Karsten
Title: Temperature dependence of indentation size effect, dislocation pile‐ups, and lattice friction in (001) strontium titanate
Language: English
Abstract:

Nanoindentations with a Berkovich type indenter were performed on (001) strontium titanate (STO) single crystal at 25 degrees C and 350 degrees C, analyzing the influence of temperature on the indentation size effect (ISE) and dislocation structure around the residual impression. It is found that the STO exhibits an ISE, which is strongly reduced at 350 degrees C compared to 25 degrees C. The dislocation structure around the residual impression has been resolved using an etch-pit technique. At 25 degrees C, the extension of the dislocation pile-ups were found to be shorter as compared to 350 degrees C. This also correlates with the smaller size effects at 350 degrees C. Peach-Koehler forces and the elastic-plastic indentation stress field were used to model the influence of the lattice frictional stress on the dislocation pile-ups. Based on an equilibrium position of the outermost dislocations, the average lattice frictional stresses were calculated to be 89 MPa and 46 MPa at 25 degrees C and 350 degrees C, respectively.

Journal or Publication Title: Journal of the American Ceramic Society
Volume: 101
Number: 1
Publisher: Wiley
Uncontrolled Keywords: dislocation etch-pits, elevated temperature, indentation size effect, strontium titanate
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
11 Department of Materials and Earth Sciences > Material Science > Physical Metallurgy
Date Deposited: 29 May 2018 05:35
Funders: The authors gratefully acknowledge funding from Deutscher Akademischer Austauschdienst (FJ)., EAP was supported by the Leibniz program of the Deutsche Forschungsgemeinschaft under RO 954/22.
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