Experimental and numerical investigation of idealized consolidation - Part1: Static compaction

In order to investigate the compaction of homogeneous and composite powders under carefully controlled conditions, idealized two-dimensional compacts were constructed using rods of aluminum and hardened steel. Special attenti on was paid to the material behavior of the rods, the die boundary conditio ns, the periodic packing arrangement, and the shape change during ejection from the dies (springback). Corresponding finite element simulations of uni axial compaction were carried out. Pressure-density relationships, over a w ide range of pressures and densities, were achieved by matching initial pac king density and accounting for springback. Springback consists of two sign ificant contributions: particle compressibility and void reopening. Deforme d particle shapes were predicted well and the role of inter-particle fricti on was found to be minor for the idealized arrangements studied. The ratio of contact pressure over current yield stress is close to 3 for homogeneous compaction, and much higher values are seen for heterogeneous compaction. As expected, the presence of hard particles greatly inhibits the densificat ion process. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.