Dynamic hot pressing of a porous non-Newtonian solid

Abstract

1. An analysis is made of the densification of porous G13 steel to demonstrate that the rheological theory of the dynamic densification of a porous non-Newtonian solid can be employed for describing the behavior of real porous solids during dynamic hot pressing. The limits of applicability of the theory are examined. 2. A method is proposed for the processing of experimental data upon the densification of materials during dynamic hot pressing. Using this method, it is possible to extract from such data useful information concerning the densification process and the mechanism of the deformation of the solid phase in a porous solid and also to distinguish between a static and a dynamic hot pressing process. 3. From the results of the analysis it follows that, during dynamic hot pressing, high pressures — exceeding by more than an order those employed in static hot pressing — are generated within a short densification time (of the order of 10−3 sec). Under the action of these pressures, the material experiences intense plastic flow. This process, whose rate is a nonlinear function of stress, is less sensitive to temperature than creep, which is linked with diffusional mass transport.