On the sintering with rigid inclusions

The sintering of porous matrices containing rigid, i.e. non-densifying, inclusions is discussed on the basis of the composite sphere model of Scherer. Recognizing that internal stresses are generated by the presence of the non-densifying inclusions, a new equation for the densification rate of the composite is proposed. It takes into account three contributions: i) the free densification strain rate, which is independent of the stresses present, ii) the strain rate due to the microscopic effect of the stresses on the sintering mechanism and iii) the macroscopic deformation strain rate induced by the stresses. This result indicates that the presence of rigid inclusions may generate higher internal stresses in the densifying compact than those calculated by the original Scherer's approach.