The effect of crystal defects on 3D high resolution diffraction peaks: a FFT-based method

Komlavi Eloh (1, 2, 3) , Alain Jacques (3, 1) , Gabor Ribarik (3, 4) , Stéphane Berbenni (2, 3)

1 IJL - Institut Jean Lamour
2 LEM3 - Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux
3 Labex DAMAS
4 ELTE - Eötvös Loránd University

Forward modeling of diffraction peaks is a potential way to compare the results of theoretical mechanical simulations and experimental X-Ray Diffraction data recorded during in situ experiments. As the input data are the strain or displacement field within a representative volume of the material containing dislocations, a computer-aided efficient and accurate method to generate these fields is necessary. With this aim, a current and promising numerical method is based on the use of the Fast Fourier Transform (FFT) method. However, classic FFT-based methods present some numerical artifacts due to the Gibbs phenomenon or ''aliasing'' and to ''voxelization'' effects. Here, we propose several improvements: first, a consistent discrete Green operator to remove ''aliasing" effects and second, a method to minimize the voxelization artifacts generated by dislocation loops inclined with respect to the computational grid. Then we then show the effect of these improvements on theoretical diffraction peaks.

Mots clés: Dislocations; diffraction; FFT-based method; Discrete Green operator; voxelization 24 artifacts; sub-voxel method; simulated diffraction peaks; scattered Intensity

Domaines: Matériaux; Mécanique [physics.med-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des solides [physics.class-ph]

Komlavi Eloh, Alain Jacques, Gabor Ribarik, Stéphane Berbenni. The effect of crystal defects on 3D high resolution diffraction peaks: a FFT-based method. Materials, 2018, 11 (9), pp.1669. ⟨10.3390/ma11091669⟩. ⟨hal-02360465⟩