Densification of powder materials in non-uniform temperature fields

The influence of temperature non-uniformity in the thermal processing of powder materials is studied theoretically in the framework of a model of a viscoelastic medium with shear and bulk (dilatational) viscosities. The contribution of thermoelastic effects to the total densification is shown not to exceed in absolute value the relatively small deformation due to thermal expansion. Stronger localized densification is shown to be possible in the vicinity of the maxima of the temperature distribution because of viscosity inhomogeneity. The possibility of explaining specific features observed in the microwave processing of powder materials in terms of these effects is discussed.