Orientation stress field analysis in polycrystalline bcc steel using neutron diffraction

Abstract

We propose a methodology associating texture determinations and strains measurements by neutron diffraction in order to analyse the stress fields within families of crystallites with the same crystallographic orientation in polycrystalline materials. This stress analysis method allows an intermediate approach between a local and a global scale characterization within the bulk of massive samples, and appears promising for coupling with modelling methods due to the statistically representative informations it provides. We report here its application to characterize in situ the mechanical behaviour under uniaxial tension of a low alloyed 16MND5 bainitic steel used for nuclear reactor pressure vessels. It appears that the selected investigated phases exhibit very different mechanical responses. A large plastic deformation heterogeneity is observed.