Three-dimensional maps of grain boundaries and the stress state of individual grains in polycrystals and powders

• Published in: Journal of applied crystallography Vol. 34; no. 6; pp. 751 - 756
• Main Authors: Poulsen, H. F., Nielsen, S. F., Lauridsen, E. M., Schmidt, S., Suter, R. M., Lienert, U., Margulies, L., Lorentzen, T., Juul Jensen, D.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England Munksgaard International Publishers 01-12-2001; Blackwell; International Union of Crystallography
• Subjects: bulk materials; computer programs; Condensed matter: structure, mechanical and thermal properties; Engineering Sciences; Exact sciences and technology; grain boundaries; Mechanics; Physics; polycrystalline materials; powders; Single-crystal and powder diffraction; strain; stress; Structural mechanics; Structure of solids and liquids; crystallography; three-dimensional mapping; X-ray diffraction and scattering; Grain boundaries; Powders; Rotation curve; Polycrystals; Three dimensional space; Residual stresses; XRD; Grain orientation; Texture; Non destructive method; Investigation method; Strains; Microstructure; Synchrotron radiation
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S0021889801014273

A fast and non‐destructive method for generating three‐dimensional maps of the grain boundaries in undeformed polycrystals is presented. The method relies on tracking of micro‐focused high‐energy X‐rays. It is verified by comparing an electron microscopy map of the orientations on the 2.5 × 2.5 mm surface of an aluminium polycrystal with tracking data produced at the 3DXRD microscope at the European Synchrotron Radiation Facility. The average difference in grain boundary position between the two techniques is 26 µm, comparable with the spatial resolution of the 3DXRD microscope. As another extension of the tracking concept, algorithms for determining the stress state of the individual grains are derived. As a case study, 3DXRD results are presented for the tensile deformation of a copper specimen. The strain tensor for one embedded grain is determined as a function of load. The accuracy on the strain is Δɛ≃ 10−4.