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Temperature dependence of indentation size effect, dislocation pile‐ups, and lattice friction in (001) strontium titanate
Author(s) -
Javaid Farhan,
Johanns Kurt E.,
Patterson Eric A.,
Durst Karsten
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15182
Subject(s) - materials science , indentation , dislocation , strontium titanate , composite material , pile , residual stress , crystallography , condensed matter physics , nanotechnology , thin film , chemistry , structural engineering , physics , engineering
Nanoindentations with a Berkovich type indenter were performed on (001) strontium titanate ( STO ) single crystal at 25°C and 350°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°C compared to 25°C. The dislocation structure around the residual impression has been resolved using an etch‐pit technique. At 25°C, the extension of the dislocation pile‐ups were found to be shorter as compared to 350°C. This also correlates with the smaller size effects at 350°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°C and 350°C, respectively.