Texture evolution and the role of grain boundaries in skeletal formation during coarsening in solid-liquid mixtures

During coarsening of high-volume-fraction solid-liquid mixtures, a solid skeleton is formed. Electron back-scattered diffraction (EBSD) analysis of Sn particles in a liquid Pb-Sn eutectic is employed to yield quantitative evidence for the mechanisms that are operative during skeletal formation. We find that the grain boundaries (GBs) play a substantial role in setting the skeletal structure; however, they do not alter the mechanisms for skeletal coarsening. Particles do not rotate into low-energy configurations to minimize the GB energy in the solid-liquid mixture. Thus, there is no particle rotation-induced coalescence. We find that coalescence is not prevalent; Ostwald ripening is the primary mechanism for coarsening in this system. Our data suggest a model for skeletal formation and the origin of the skeletal stability. This model indicates that the primary factor in determining skeletal stability is the number of GB contacts. We recommend two methods to tailor the number of GBs and to engineer the properties of these solid-liquid mixtures.