Anisotropy features of phase and particle spatial pair distributions in various matrix/inclusions structures

The morphology anisotropy of various matrix/inclusions structures is investigated by means of phase pair covariograms and skeletisation by influence zones (SKIZs), specializing on cases of not all congruent inclusions. The structures of concern are either real or numerical ones. Analyzed data are either 2D or 3D, the latter ones being obtained, for the real materials, from X-ray micro-tomography. Shape and orientation differences between inclusion types appear to induce a short range heterogeneity scale where compact groups of shape-similar inclusions form, especially to achieve non-dilute concentrations. Resulting spatial pair distributions of phases and of inclusion centres are generally not all of a same symmetry, such that the related overall distributions can hardly be taken as uniformly ellipsoidal. Alternative relevant assumptions for modelling purposes are proposed and commented.