Modelling powder compaction - From a pressure-density law to continuum mechanics

In this paper, three basic hypotheses are proposed. regarding the effects of porosity and work hardening on powder compaction for building a new pressure-density relation. After a short validation on some hard powders. complementary hypotheses are used for generalising the density description as a function of hydrostatic pressure and deviatory stress. The model is then tested using triaxial characterisations from another author. Lastly. it is shown that the modelling parameters. to which a physical meaning is given. can be determined from two simple experiments, such as isostatic compaction and die pressing. This represents a drastic saving in time for characterising the compaction behaviour of hard powder. PM/0979 At the time the work was carried out the author was at the Centre Europeen de Recherche en Metallurgie des Poudres, 54. Avenue Rhin et Danube, 38100 Grenoble, France. The author (jacques.secondi@sandvik.com) is now with Sandvik Hard Materials. Quartier de la Gare, F-26210 Epinouze. France. Manuscript received 26 September 2001: accepted 15 April 2002. (C) 2002 IoM Communications Ltd. Published by Maney for the Institute of Materials. Minerals and Mining.