Variations in the local crystallographic orientation due to the presence of geometrically necessary dislocations and dislocation boundaries smear the distribution of intensity near Laue reflections. Here, some simple model distributions of geometrically necessary dislocations were used to estimate the dislocation tensor field from the intensity distribution of Laue peaks. Streaking of the Laue spots was found to be quantitatively and qualitatively distinct depending on the ratio between the absorption coefficient and the geometrically necessary dislocation density gradient. In addition, different slip systems cause distinctly different Laue-pattern streaking. Experimental Laue patterns were therefore sensitive to stored dislocations and geometrically necessary dislocations. As an example, white beam micro-diffraction was applied to characterize the dislocation arrangement in a deformed polycrystalline Ni grain during in situ uniaxial tension.

Gradients of Geometrically Necessary Dislocations from White Beam Microdiffraction. R.I.Barabash, G.E.Ice, J.W.L.Pang: Materials Science and Engineering A, 2005, 400-401, 125-31