Study of powder densification under hydrostatic loads at high temperatures using finite element method

Abstract

Many different constitutive models that describe the behaviour of metal powder during hot isostatic processes are found in literature. A quantitative comparison of these material laws shows a huge discrepancy among the different existing models. This reveals the high sensitivity of the mechanical behaviour of porous materials to the shape, arrangement and distribution of particles and pores.In order to clarify these discrepancies, the compaction behaviour under high temperature hydrostatic loads for a Nickel-based superalloy has been experimentally characterized. In parallel, three different particle/pore configurations have been analysed at a mesoscopic scale by means of FEM using representative volume elements (RVEs) with periodic boundary conditions. The overall macroscopic response of each RVE has been obtained by a homogenization procedure.The results confirm the high sensitivity of the overall mechanical response to the microscopic arrangement of pores and particles.