AN ANISOTROPIC CONTINUUM MODEL FOR THE SINTERING AND COMPACTION OF POWDER PACKINGS

A continuum model is presented for the early to intermediate stages of densification of powder packings during sintering and compaction. Material points in a particle far from a contact are assumed to deform according to the macroscopic deformation rate. Sintering tractions on the particle surfaces appear as a sintering stress that, in the isotropic case, reduces to a sintering pressure. The state is described by the orientational distribution of contacts, the contact area and length of a link connecting particle centroids (which are functions of orientation), and the coordination number and volume fraction of particles. The model is completed by specifying evolution equations for the state. Model predictions are presented for isotropic and axisymmetric cases. The predictions are compared with experiments conducted with aluminum powder compacts.