Accession Number : ADA131514

Title :   Hot Isostatic Pressing of Ceramic Powder Compacts.

Descriptive Note : Annual rept. no. 1, Jun 82-Jun 83,


Personal Author(s) : Wills,R R ; McCoy,J K ; Markworth,A J ; McCoy,L G ; Muttart,L E

PDF Url : ADA131514

Report Date : 28 Jun 1983

Pagination or Media Count : 97

Abstract : Several mechanisms contribute to the densification of ceramics during HIP. These can potentially be related to the kinetics of densification by the use of mechanism maps and a predictive methodology derived for determining parameter selection during HIP. The constitutive equation for final stage densification have been critically examined in terms of their underlying assumptions and the effects of changes in pore size, grain size, temperature, pressure, diffusion coefficient, density and the presence of residual gas pressure. A new algorithm for calculating and plotting mechanism maps has been derived. This algorithm reduces the number of data points needed to construct a complete map be a factor of 30. Initial experiments performed at 1100 C and 102 MPa (15,000 psi) showed that a very small amount of grain growth occurred. Correlation of the experimental data with the theoretical predictions is quite good; if it is assumed that 1% residual porosity is a result of entrapped gases then excellent agreement between theory and experiment exists. Although the constitutive equations are supposed to be most applicable during the latter stages of densification, good agreement exists throughout the whole densification range.

Descriptors :   *Ceramic materials, *Isostatic pressing, *Packing density, Powders, Hot pressing, Porosity, Grain size, Diffusion coefficient, Physical properties, Mechanical properties, Theory, Algorithms, Mathematical models

Subject Categories : Ceramics, Refractories and Glass
      Theoretical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE