Three dimensional characterization and modeling of particle reinforced metal matrix composites: part I - Quantitative description of microstructural morphology

In this first of a two part sequence of papers, 3-D microstructures of Si p article reinforced aluminum matrix composites are computationally construct ed by assembling digitally acquired micrographs obtained by serial sectioni ng. The material samples considered vary in volume fraction and in particle size. Furthermore, equivalent microstructures with actual particles replac ed by ellipses (in 2-D) or ellipsoids (in 3-D) are computationally simulate d for efficiency. The equivalent microstructures are tessellated by a parti cle surface based algorithm into a mesh of Voronoi cells. Various 3-D chara cterization functions are developed to identify particle size, shape, orien tation and spatial distribution in the actual materials and to compare with 2-D micrographs. Through this analysis, differences between 2- and 3-D cha racterization are established. Results indicate that it may not be sufficie nt to use 2-D section information for characterizing detailed microstructur al features like particle shapes, orientations and near-neighbor distances. The second part of this sequence of papers will describe the important rel ationship of these features to damage evolution in these same materials. Th is sequence of papers is perhaps one of the first on 3-D physical character ization of the phase and damage structure for this class of materials. (C) 1999 Elsevier Science S.A. All rights reserved.