Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10621004 | Acta Materialia | 2006 | 9 Pages |
Abstract
Incipient plasticity in magnesium oxide single crystals has been investigated by nanoindentation with a spherical indenter. For very low loads, the surface deformation can be limited to a single slip line, making modelling of the deformation easier. The recently developed nanoetching technique has been used to investigate the corresponding dislocation structure. Single pile-ups of a few dislocation half loops have been observed and fully characterised. A simple elastic model, based upon the calculation of the Peach Koehler force induced by the pile-ups and the spherical indenter stress field, has been used to determine the equilibrium positions of dislocations in these pile-ups. A comparison between the experimental and calculated structures has led to the determination of the lattice friction stress for edge and screw dislocations in magnesium oxide single crystals. This stress is found to be 65Â MPa for edge dislocations and 86Â MPa for screw dislocations.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Y. Gaillard, C. Tromas, J. Woirgard,