Intragranular Stress and Dislocation Density in Cu

Jun Jiang, Ben Britton and Angus Wilkinson have been working on EBSD mapping of local stresses and dislocation density distributions in deformed ploycrystals.
We have taken Cu with an average grain size of ~30 microns as a model starting material. The maps allow correlations between the local stress, the local dislocation density and the position relative to microstructural features such as grain boundaries and triple junctions to be explored. Grain orientations also allow correlation with Schmid and Taylor factors.



Cu 6% Strain



In general the magnitude of the local shear stress and the geometrically necessary dislocation density are higher near grain boundaries, though not near all boundaries. The shear stress and dislocation density are found to be correlated (correlation coefficient of +0.4).


References

Probing Deformation and Revealing Microstructural Mechanisms with Cross-Correlation-Based, High-Resolution Electron Backscatter Diffraction
TB Briton, J Jiang, PS Karamched, AJ Wilkinson
JOM (2013) available online 31 July 2013
doi:10.1007/S11837-013-0680-6

Mapping type III intragranular residual stress distributions in deformed copper polycrystals
J Jiang, TB Briton, AJ Wilkinson
Acta Materialia (2013), vol. 61, 5895–5904
doi:10.1016/j.actamat.2013.06.038

Measurement of geometrically necessary dislocation density with high resolution electron backscatter diffraction: Effects of detector binning and step size
J Jiang, TB Britton and AJ Wilkinson
Ultramicroscopy, (2013), vol. 125, 1-9
doi:10.1016/j.ultramic.2012.11.003

Accumulation of geometrically necessary dislocations near grain boundaries in deformed copper
J Jiang, TB Britton, AJ Wilkinson
Philosophical Magazine Letters, (2012), vol. 92, 580-588
doi:10.1080/09500839.2012.700412





Contact: Angus Wilkinson