Effective area in powder compacts under uniaxial compression

A simple equation is proposed for calculating the effective area in a powder compact at any stage of a uniaxial compression process. In this equation, the effective area is a function of both the sample porosity and the tap porosity of the starting powder. The tap porosity determines to a great extent the pore structure of the compact, since this depends on the size, shape and distribution of powder particles. The proposed equation was evaluated by using a computer simulation of the deformation process for a simple cubic packing, and direct measurements on SEM images of powder compacts prepared at different pressures. Results are in very good agreement with theoretical predictions.