X-ray microdiffraction and strain gradient crystal plasticity studies of geometrically necessary dislocations near a Ni bicrystal grain boundary

• Published in: International journal of plasticity Vol. 25; no. 5; pp. 920 - 941
• Main Authors: Ohashi, Tetsuya, Barabash, R.I., Pang, J.W.L., Ice, G.E., Barabash, O.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-05-2009; Elsevier
• Subjects: Bicrystals; Crystal plasticity; Crystals; Dislocations; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Grain boundaries; Inelasticity (thermoplasticity, viscoplasticity...); Nickel; Physics; Plasticity; Polycrystalline material; Simulation; Solid mechanics; Strain; Stress relaxation; Structural and continuum mechanics; Grain boundaries; Crystal plasticity; Stress relaxation; Polycrystalline material; Dislocations; Scanning electron microscopy; Crystallographic direction; Solid inclusion; Uniaxial tension stress; X ray radiography; Polycrystal; Experimental study; Modeling; Tension test; Dislocation; Grain boundary; Finite element method; Inelasticity; Strain gradient; Plasticity; Localization; Non local theory; Bicrystal
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/j.ijplas.2008.04.009

We compare experimental measurements of inhomogeneous plastic deformation in a Ni bicrystal with crystal plasticity simulations. Polychromatic X-ray microdiffraction, orientation imaging microscopy and scanning electron microscopy, were used to characterize the geometrically necessary dislocation distribution of the bicrystal after uniaxial tensile deformation. Changes in the local crystallographic orientations within the sample reflect its plastic response during the tensile test. Elastic strain in both grains increases near the grain boundary. Finite element simulations were used to understand the influence of initial grain orientation and structural inhomogeneities on the geometrically necessary dislocations arrangement and distribution and to understand the underlying materials physics.