An automated method to analyze separately the microtextures of primary alpha_p grains and the secondary alpha_s inherited colonies in bimodal titanium alloys

摘要

A method was developed to automatically recognize the orientations of primary alpha_p grains and secondary alpha_s colonies of a bimodal titanium alloy, on the orientation map. Both populations of grains are dissociated by correlating the Electron Back Scattering Diffraction data with the corresponding Back Scattered Electron image on which a high chemical contrast is observed between the alpha_p and (alpha_s+beta_(residual)) phases. The whole data processing is successfully applied to a large EBSD map of a bimodal IMI 834 billet. This allows to discuss the contribution of alpha_p grains and alpha_s colonies to the sharp texture heterogeneities observed in the billet.