Numerical simulation of thermoelectric phenomena in field activated sintering /

by Zhang, Jing.; Zavaliangos, Antonios.; College of, Drexel University.

Numerical Simulation of Thermoelectric Phenomena in Field Activated Sintering Jing Zhang Antonios Zavaliangos, Ph. D. The field activated sintering technique (FAST) is a powder consolidation process that involves the application of pulsed current and pressure. Compared with hot pressing and hot isostatic pressing, FAST is a demonstrated rapid densification process that has the potential to minimize grain growth, which is crucial to achieving excellent mechanical properties. In this study, a coupled thermal-electric-densification framework for the design and optimization of FAST-type processes has been proposed and implemented into a finite element package (ABAQUS). A detailed evaluation of the accuracy of the model has been carried out for electrically conductive and insulating materials. The evaluation, compared with experimental measurements, indicated that the model provided a reasonably accurate prediction of the thermal and electric responses. A discrete finite element method was also developed to determine the effective thermal conductivity in a particulate system with a realistic microstructure. In addition to the usual examination of its dependence on relative density, an anisotropy of conductivity was found as a result of the application of nonisostatic stress. This was confirmed qualitatively by experimental observation. Finally, an exploration of FAST simulation of a complex shape part was attempted. 1