The morphology of high volume fraction solid-liquid mixtures: An application of microstructural tomography

Three-dimensional (3-D) images of the skeletal morphology that forms at a high volume fraction of solid during Ostwald Ripening are reconstructed from two-dimensional (2-D) sections. These images illustrate the topology of the skeleton, including the circuitous and multiple paths through which particles in the skeleton connect. Particles that connect by grain boundaries form chains that can cross-link and intersect. These chains can also give rise to multiple indirect contacts between two particles. Direct interparticle contacts can occur via grain boundaries or thin liquid films. All particles connect to the skeletal network by such ''contacts''; there are no isolated particles or clusters within our 3-D reconstruction. Shape accommodation is prevalent. The particle morphology is a strong function of the spatial arrangement of neighboring particles. We find that isolated 2-D sections are thus limited in characterizing the microstructure. The relationship between the 3-D microstructure of the skeleton and its structural stability is discussed. (C) 1997 Acta Metallurgica Inc.