Measurement of spatial stress gradients near grain boundaries

A correlative method based on electron back scattered diffraction and focused ion-beam-digital image correlation slit milling technique was used to quantitatively determine spatially resolved stress profiles in the vicinity of grain boundaries in pure titanium. Measured local stress gradients were in good agreement with local average misorientation and experimentally calculated geometrically necessary dislocation densities. Stress profiles within few hundred to thousand nanometers near the grain boundary display a local minimum, followed by a typical Hall-Petch type variation of one over square root of distance. The observed trends allude to local stress relaxation mechanisms active near grain boundaries. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.