DETERMINATION OF THE MECHANICAL RESPONSE OF SINTERING COMPACTS BY CYCLIC LOADING DILATOMETRY

Determination of the mechanical response of a powder compact during de nsification is critical in analyzing defect formation and macroscopic dimensional changes, particularly in systems where constrained sinteri ng is involved, Cyclic loading dilatometry is proposed as a novel appr oach in evaluating the mechanical response of the sintering compact, i ncluding sintering pressure, elastic modulus, and viscosity. The advan tage of this technique is that only one experiment is needed to determ ine the equilibrium elastic and viscous properties of a sintering mate rial at any temperatures for any given heating schedule, and no interr upted tests are necessary, This methodology is demonstrated for sinter ing compacts of Al2O3, Ce-TZP, and their composite mixture. The loadin g dilatometric data showed that the compact behaved elastically prior to the onset of sintering and during the very initial stages of sinter ing, which was followed by a transition leading to a viscous behavior for the latter part of the densification, Application of different loa d levels, ranging from 0.25 to 1 MPa, showed that the compact viscosit y is essentially linear within the applied stress range at temperature s greater than 1100 degrees C.