The deformation and densification of an array of metal-coated fibres

The densification of an array of metal-coated fibres (MCFs) by rate-independent plasticity is examined in this paper. The finite element method is used to simulate both hydrostatic and closed-die compaction of the MCFs. The slip-line fields of the deformation mechanisms are compared with the finite element predictions and used to address the current disagreement in the literature as to the source of the softening in the contact pressure of an array of MCFs. The accuracy of the relative density based on the current densification model of uniform redistribution of material on the free surface of a particle is also examined. We find that this assumption overestimates the relative density for both hydrostatic and closed-die compaction. The evolution of the relative density for both modes of compaction is compared for a strain-hardening metal coating. The prediction of the relative density based on J(2) flow theory is consistently lower than that based on deformation theory for all values of the strain-hardening exponent considered. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.