Porosity evolution during sintering in tungsten powders of different grain size
- Univ. Wien (Austria). Inst. fuer Experimentalphysik
- Metallwerk Plansee, Reutte (Austria)
In recent work the densification behavior during sintering was investigated by neutron small angle scattering techniques. This experimental method allows the determination of the total porosity surface even in stages where the porosity is closed. In the literature most investigations of the sintering process deal with the time evolution of density at different temperatures. The time evolution of sintering is determined by various mechanisms like surface diffusion, grain boundary diffusion and bulk diffusion contributing to a varying extent to the densification during the different stages of sintering. Generally, the density change with time follows quite different curves if investigated as a function of temperature. Neutron small angle scattering measures the total porosity surface F via the Porod law which relates the scattered intensity I(Q) to F by the formula I(Q) {alpha} F/Q{sup 4}, where Q is the transfer of momentum. In the previous work on the sintering behavior of Mo, Nb, Ta and Al{sub 2}O{sub 3} ceramics the measured F values were related to the total cavity volume V during the different stages of the sintering process. The present work was undertaken in order to further corroborate the trajectory concept and, in particular, to investigate its dependence on the initial state of the powder. The authors present a neutron small angle scattering investigation of the sintering behavior of a series of tungsten powders with several different initial grain sizes.
- OSTI ID:
- 205225
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 7 Vol. 34; ISSN 1359-6462; ISSN XZ503X
- Country of Publication:
- United States
- Language:
- English
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