Temperature dependence of indentation size effect,dislocation pile‐ups,and lattice friction in (001) strontium titanate |
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| Authors: | Farhan Javaid Kurt E. Johanns Eric A. Patterson Karsten Durst |
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| Affiliation: | 1. Physical Metallurgy Division, Materials Science Department, Technische Universit?t Darmstadt, Darmstadt, Germany;2. Nanomechanics Inc., Oak Ridge, Tennessee;3. Nonmetallic‐Inorganic Materials, Materials Science Department, Technische Universit?t Darmstadt, Darmstadt, Germany;4. U.S. Naval Research Laboratory, Washington, DC |
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| Abstract: | 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. |
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| Keywords: | dislocation etch‐pits elevated temperature indentation size effect strontium titanate |
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