Evaluation of microstructural features on heavily deformed metals by X-ray peak broadening on different brilliance apparatuses

R.E. BOLMARO; N. S. DE VINCENTIS; P. SUZUKI; H-G. BROKMEIER

JOINVILLE

Congreso; XX Congresso Brasileiro de Engehneria e Ciencia dos Materiais CBECiMat; 2012

X ray diffraction is a well developed technique to characterize materials? microstructure (grain size, dislocation density, twinning, etc.) by measuring peak broadening for a set of planes and by using appropriate tools for analysis. The most accessible X ray source is currently the regular laboratory based X-ray diffraction machine using an X-ray tube. Parallel beam arrangement with monochromators or X-ray optical fiber lenses are the suggested set ups for this kind of technique. Properly toned they provide controllable machine peak broadening on the order of one half the common microstructure induced peak width. Further improvement is obtained by using increasing energy and more brilliant synchrotron X ray sources. Brilliance, a combined measure of intensity, beam divergence and wavelength dispersion, might influence the kind, scale, quality and accuracy of the detected microstructural features. The current paper deals with the determination of grain sizes and dislocation storage by using three levels of brilliance, those corresponding to a laboratory based X ray source, the Brazilian synchrotron beam line XRD1 inCampinas(Brazil) and at the Petra III based HEMS line inHamburg(Germany). The main purpose is the evaluation of the capabilities of the tree different gadgets by measuring peak broadening on steel and Ti samples deformed by rolling and ECAE and later heat treated. The data have been processed by the extended Convolutional Multiple Whole Profile method and the calculation of Generalized Pole Figures for FWHM and peak shift.