Kink-Pair Mechanism in \langle 001\rangle SrTiO3 Single Crystal Compression-Deformed at Room Temperature

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We have analyzed the microstructure of \langle 001\rangle SrTiO3 single crystal deformed using compression at room temperature using transmission electron microscopy. A representative stress--strain (\sigma--\varepsilon) curve is established, similar to that for metals it consists of three hardening stages before failure occurs at a strain \varepsilon = 19\pm 2%. Dislocation analysis suggests that the primary slip systems in [011](0\bar{1}1) and [0\bar{1}1](011) are activated in the \sigma--\varepsilon curve stress plateau region usually addressed as easy glide. Three characteristic features are identified from samples deformed to stage I hardening by easy glide: (a) rectangular glide loops, (b) collinear partials, and (c) kink pairs. Dislocations have predominantly pure edge character. Kink pairs are observed only on the edge segments suggesting that screw dislocations have higher mobility. In easy glide, the migration and annihilation of kink pairs occurring on both the trailing and leading partials lends support to a previous report by Castillo-Rodríguez and Sigle (2011) that dislocation glide is controlled by the long-segment limit of a kink-pair model.
2011-10-25