Electroconsolidation is a process for densifying complex-shaped parts using electrically conductive particulate solids as a pressure-transmitting medium. The part is immersed within a bed of the particulate medium contained in a die chamber. Heating to sintering temperature is achieved by resistive heating of the medium while applying compaction pressure. The process is capable of ultra-high temperatures and short cycle times, and it offers the potential for low processing costs. Control of the process as well as selection of process conditions require knowledge of the temperatures within the die. Temperature gradients will exist because of the high heating rate and because of variations of density and electrical resistivity of the medium due to the presence of the part. Direct measurement of temperature with thermocouples or other conventional means is impractical because of the high temperatures, high currents, and high pressures. Therefore, a computer model was developed to predict the temperature as a function of time and applied voltage for any location in the die. The computer model contains three parts: a geometrical model to approximate the density and resistivity variations in the medium, a finite-element model to calculate the rate of resistive heating within each element, and a finite-difference model to calculate the temperature distribution based upon solution of the heat-transfer equations. Predicted temperatures have been shown to be in excellent agreement with measurements.
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