Finite-element calculations of the lattice rotation field of a tensile-loaded nickel-based alloy multicrystal and comparison with topographical X-ray diffraction measurements

Abstract

A new experimental measurement technique using synchrotron radiation is applied to determine the curvature of the crystallographic lattice within a grain of a multicrystalline specimen after uniaxial tensile loading. The experimental results are compared to a three-dimensional finite-element model, which is based on a classical crystal-plasticity law. The model takes the entire microstructure of the multicrystal into account. A small-strain and small-rotation formalism allows calculation of the orientation matrix at each integration point for each deformation step. A good agreement of the experimental and numerical data has been found. The experimental technique is based on image-data processing. The development of data-treatment algorithms allows distinction to be made between the regular crystallographic curvature and the random mosaic distribution always present in polycrystalline materials.