Combined effects of interstitial and laplace pressure in hot isostatic pressing of cylindrical specimens

Laura Galuppi, Luca Deseri

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Sintering of precompacted metallic and ceramic micro and nanopowders is a complex problem influenced by several factors. We quantify the influence of both local capillary stresses acting at the surface of one pore or particle (usually referred to as Laplace pressure) and the gas pressure in pores during sintering of precompacted metallic (micro/nano)powdered cylinders. The latter influences only the third phase of sintering, that is, the phase in which the porosity is closed. The isostatic pressing loading mode, which also covers the case of free sintering, is considered. Whereas the Laplace pressure is demonstrated to have a beneficial effect on sintering, the gas pressure acts against the reduction of the porosity, causing an increase in sintering time. This contribution could reach the sum of the stress due to loading and the interstitial pressure, thereby preventing the desired porosity to be reached. For the sake of illustration, a specific aluminum-zinc-magnesium-copper alloy is examined in this paper. The purpose is to estimate the effects of sintering time and residual porosity and to determine thresholds under which the contributions described above are negligible. In order to determine the effects of Laplace and gas pressure in pores on the stability of the process, a high-order perturbation analysis has been performed.

Original languageEnglish (US)
Pages (from-to)51-86
Number of pages36
JournalJournal of Mechanics of Materials and Structures
Volume9
Issue number1
DOIs
StatePublished - Mar 2014

Keywords

  • Ceramic compaction
  • Hot isostatic pressing
  • Interstitial and laplace pressure
  • Metallic powder compaction
  • Nanopowders
  • Powder technology
  • Sintering

ASJC Scopus subject areas

  • Mechanics of Materials
  • Applied Mathematics

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