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Combined effects of
interstitial and Laplace pressure in hot isostatic pressing
of cylindrical specimens
Laura Galuppi and Luca Deseri |
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Vol. 9 (2014), No. 1, 51–86
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Abstract |
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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. |
Keywords
sintering, powder technology, nanopowders, hot isostatic
pressing, interstitial and Laplace pressure, ceramic
compaction, metallic powder compaction
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Milestones
Received: 8 July 2013
Revised: 9 September 2013
Accepted: 6 October 2013
Published: 23 March 2014
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Authors |
| Laura Galuppi | ||
| Dipartimento di Ingegneria
Industriale Università degli Studi di Parma Viale G. P. Usberti 181/A 43124 Parma Italy |
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| Luca Deseri | ||
| DICAM, Group of Solid and Structural
Mechanics University of Trento via Mesiano 77 38123 Trento Italy |
Department of Civil and
Environmental Engineering and Department of Mechanical
Engineering Carnegie Mellon University 5000 Forbes Avenue Pittsburgh, PA 15213 United States |
Department of Nanomedicine TMHRI-, The Methodist Hospital Research Institute 6565 Fannin Street MS B-490 Houston, TX 77030 United States |
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