Development of diffraction-amalgamated grain-boundary tracking technique and its application to polycrystalline metals

Abstract

By amalgamating a transmission X-Ray diffraction (XRD) experiment with grain boundary tracking (GBT) that has been developed by the present authors by combining the X-ray micro-tomography (CT) and the gallium-enhanced grain boundary visualization techniques, a novel method which provides accurate crystallographic information of individual grains during deformation has been created. The developed technique, which is called diffraction-amalgamated grain boundary tracking (DAGT) technique, is non-destructive for in-situ characterizing of bulk materials, which allows for close to deformation and fracture analysis of metals. Employing near field XRD analysis with a thin collimated X-ray beam, the algorithms developed for DAGT identifies which diffraction spots are related to which grain; consequently, providing a description of the misorientation between grains. DAGT also realizes micron-level analysis of grain morphologies and local stain distribution in 3-dimensions (3D) on the basis of CT observation, enabling the crystallographic interpretation of localized deformation without being affected by blurring of diffraction spots caused by deformation. An Al-3mass%Cu alloy was used for demonstration purpose.