Experimental and numerical analysis of the particle size effect on the densification behaviour of metal injection moulded tungsten parts during sintering

The sintering behaviour of metal injection moulded tungsten components using fine (FSSS 0.4 to 1 mu m) and coarse (FSSS 5.0 to 7.0 mu m) powder has been investigated via dilatometric and three-point bending tests in a Setaram (c) analyser under a pure hydrogen atmosphere at temperatures up to 1700 degrees C. The experimental results have been applied to determine the material parameters in the viscoplastic constitutive law for continuum sintering model, which has been implemented in a finite element code ABAQUS software via the user subroutine UMAT for predicting the final shrinkage and density distribution of the sintered components. The effect of particle size of the powder on the densification behaviour, sintering activation energy, and sintering stress has been analysed. (C) 2014 Elsevier B.V. All rights reserved.