Hierarchically-Clustered Structures: Formation During Colloidal Processing and Evolution During Sintering.

摘要

The research presented in this report examined the formation and microstructural evolution of colloidally consolidated systems during sintering. The microstructural evolution of a hierarchically-clustered system was treated as a whole. The main goals were (i) to develop a methodology for predicting the evolution of hierarchically-clustered structures during densification and (ii) to develop experimental techniques for modifying the hierarchical structures through colloidal consolidation techniques. Experimental and theoretical modeling studies showed that all powder compacts eventually approach a steady-state grain-size distribution regardless of the original state of the colloidally consolidated compact. During densification, all microstructures followed unique paths dependent upon the initial state of the colloidal dispersion (dispersed or flocculated suspensions), but the final microstructure always approached an equilibrium distribution independent of the initial state of the colloidal dispersion (dispersed or flocculated suspensions), but the final microstructure always approached an equilibrium independent of the initial state. (JS)