Cohesion and dilatation of powder compacts containing hard phase particlesunder highly deviatoric stress states

The effect of hard particles in compacted powders is studied under highly d eviatoric stress states. The soft matrix powder is pure aluminum while the hard particles are W2C particles. The behavior of compacts with volume frac tions of hard particles up to 60% is investigated. Diametral compression an d simple compression tests are carried out both at room temperature and at 450 degrees C. The diametral compression test allows to submit the compact to a stress state with substantial tensile components. The dilatant behavio r of composite compacts has been studied under simple compression condition s at room temperature. Different volume fractions of hard particles and por osity content are investigated for both test conditions. It is shown that t he macroscopic effect of the hard particles is a decreasing function of the stress triaxiality. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.