CONICET | Buscador de Institutos y Recursos Humanos

The study of the microstructure of a material is of great interest because it is intimately related to its mechanical properties. Nowadays there are many different techniques that could be used for that purpose, allowing scientists to obtain information at different characteristic scales, from local to average quantities. In the latter case it is possible to obtain microstructural data through the analysis of peak broadening in an x-ray diffraction experiment. The x-ray patterns can be analyzed using a microstructural model such as the Williamson-Hall (W-H) method and the Convolutional Multiple Whole Profile method (CMWP), which allow estimating the density of dislocations and the average grain size when the samples do not present any preferential orientations. In the present work two sets of stainless steel F138 were analyzed. One set of samples were pressed through an ECAP die once and twice and other set of samples were rolled to 70% reduction and then annealed for 60 minutes at 600º, 700º, 800º and 900ºC. The diffraction patterns were obtained using a Phillips XPert Pro MPD diffractometer, with Cu tube and graphite monochromator, and also the XRD1 beamline at the Laboratorio Nacional de Luz Sincrotron at Campinas. The samples were also analyzed using the Orientation Imaging Microscopy software, implemented in a FEI Quanta 200 FEG-SEM microscope with an EBSD detector. The average grain size and the density of dislocations for these samples were estimated using the Williamson-Hall plot, and then compared with the results obtained using the Convolutional Multiple Whole Profile software. Both techniques proved to be very useful for microstructural analysis, showing similar results for each sample and the same behavior for growing deformation steps.