The research objective of this award is to develop a field-activated processing technology for synthesizing bulk nanostructured ceramics (grain size < 100 nm) from micrometer-sized starting powders. The effects of processing parameters, such as electric current density, heating rate, frequency of pulse, sintering temperature and holding time, on microstructural evolution and densification of materials will be experimentally investigated to achieve an understanding of the important processing parameters, which control the field-activated processing of nanostructured ceramics. Analytical models will be developed to study the effects of electrothermal-mechanical interactions on the field-activated consolidation of materials and on the formation of nanostructured materials. The theoretical results will be correlated to the experimental findings to obtain a fundamental understanding of the dominant mechanisms controlling the processing. Mechanical testing will be performed to characterize the mechanical behavior of the nanostructured materials and to establish the mechanical property-microstructural relationships of the resultant materials.
If successful, the results of this research will lead to a fundamentally new processing technology for synthesizing bulk nanostructured ceramics and potentially to the development of functionally nanostructured materials through the field-activated processes. The primary goal of this work is to determine the key processing conditions that control the formation of nanostructures. The important processing conditions may include distribution of electric current through the consolidated material, input of electric energy into the material, and electrothermal-mechanical interactions. Understanding the fundamental mechanisms in controlling the field-activated processing will help to determine the optimal condition for achieving homogeneous bulk nanostructured ceramics and to improve the design methodology for industrial production of bulk nanostructured ceramics. The proposed work will also contribute to numerical modeling for nonlinear electrothermal-mechanical problems.