Correlation between the particle size, pore size, and porous structure of sintered tungsten
- 401 Downloads
It has been established that the maximum size of pore channel constrictions D1 is close to the mean size of pore sections in microsections of porous skeletons (γ-=22–44%) from tungsten powders of 1- to 5-μm mean particle size. A rapid method of assessment of an integral fineness characteristic of a tungsten powder is proposed consisting in the determination of the pore size D1 in a compact (γ-c=25–45%), followed by the calculation of the mean size of agglomerated particles with Kozeny's formula. The densification of compacts from tungsten powders of 4-μm particle size at sintering temperatures of about 0.6 Tmelt is a result of decrease in the number of pores and increase in the equivalent size of agglomerated particles. In this process the mean pore section size determined by the metallographic method remains unchanged during sintering, which corresponds to a statistical model of a porous solid in the rheological theory of sintering.
KeywordsParticle Size Pore Size Tungsten Statistical Model Porous Structure
Unable to display preview. Download preview PDF.
- 1.L. A. Vermenko, O. I. Get'man, S. P. Rakitin, and V. V. Skorokhod, “Effect of heat treatment on the densification behavior of porous bodies from fine tungsten powders during sintering,” Poroshk. Metall., No. 11, 25–31 (1981).Google Scholar
- 2.O. I. Get'man, S. P. Rakitin, and V. V. Skorokhod, “Rheological and thermal activation analyses of the sintering kinetics of tungsten powders,” Poroshk. Metall., No. 10, 27–32 (1984).Google Scholar
- 3.V. V. Skorokhod, L. A. Vermenko, O. I. Get'man, et al., “Electron-optical investigation of the sintering kinetics of tungsten powders of spherical particle shape. I. Experimental investigation of the sintering of tungsten powders,” Poroshk. Metall., No. 5, 11–14 (1987).Google Scholar
- 4.V. V. Skorokhod, L. A. Vermenko, O. I. Get'man, and S. P. Rakitin, “Electron-optical investigation of the sintering kinetics of tungsten powders of spherical particle shape. II. Correlation between contact growth kinetics and shrinkage kinetics,” Poroshk. Metall., No. 6, 20–28 (1987).Google Scholar
- 5.S. V. Belov, Porous Metals in Machine Construction [in Russian], Mashinostroenie, Moscow (1981).Google Scholar
- 6.J. P. Jernot, J. L. Chermant, and M. Coster, “The mean free path in the porous phase of sintered materials,” Powder Technol.,30, No. 1, 31–35 (1981).Google Scholar
- 7.“Powder metallurgical materials. Method of pore size determination,” GOST 26849-86, Mar. 26, 1986.Google Scholar
- 8.V. S. Kovalenko, Metallographic Reagents (Handbook) [in Russian], Metallurgiya, Moscow (1981).Google Scholar
- 9.V. V. Skorokhod, Rheological Principles of Sintering Theory [in Russian], Naukova Dumka, Kiev (1972).Google Scholar
- 10.V. V. Skorokhod and S. M. Solonin, Physicometallurgical Principles of Powder Sintering [in Russian], Metallurgiya, Moscow (1984).Google Scholar