Anisotropic sintering stress for sintering of particles arranged in orthotropic symmetry

Many sintering bodies shrink in an anisotropic manner when the particle packing is not isotropic. The thermodynamic driving force for the anisotropic shrinkage, i.e. the sintering stress tensor, is determined numerically for an open pore structure with orthotropic symmetry in three dimensions. The sintering stress tensor is calculated rigorously by the energy method, the force balance method and the volume averaging method. The deviatoric component of sintering stress is approximately proportional to the logarithm of the aspect ratio of the orthorhombic volume element, and acts so as to deform the elongated particles to be more isotropic in most cases.