ISSN 1063-7842, Technical Physics, 2007, Vol. 52, No. 10, pp. 1306–1315. © Pleiades Publishing, Ltd., 2007. Original Russian Text © G.Sh. Boltachev, N.B. Volkov, S.V. Dobrov, V.V. Ivanov, A.A. Nozdrin, S.N. Paranin, 2007, published in Zhurnal Tekhnicheskoœ Fiziki, 2007, Vol. 77, No. 10, pp. 58–67. 1306 INTRODUCTION Application of high pulsed magnetic fields in pow- der compaction has been thoroughly studied to date. Sandstrom [1] in 1964 pioneered electrodynamic com- paction of powders in a tube that squeezes when sub- jected to the pulsed magnetic field of the self-current (the so-called Z-pinch scheme). Later, Mironov [2] implemented the method of electrodynamic compac- tion by tube expansion (a powder to be compacted is placed between a soft metallic tube with a solenoid inside and a rigid die mold. A high magnetic field of the solenoid makes the tube expand in the radial direction, thereby providing compaction.). Radial inductive com- pression of metallic sheaths, known as Θ pinch, has also found wide application [3]. Recently, pulsed mag- netic methods have come into use for molding nanom- eter-size powders [4–6]. Alumina compacts with void- age θ less than 0.3 have been produced by uniaxial compaction [4]. Because of the unusual properties of nanopowders (strong particle–particle interaction and a high surface energy), the pulsed magnetic method has turned out to be more effective [5] than the conven- tional static and shock-wave techniques of nanopowder compaction. A considerable insight into the processes attendant on compaction of structurally inhomogeneous bodies has been gained in terms of the plasticity theory [7–17]. In particular, it has been established [9–11] that not only the geometrical factor (a decrease in the voidage) determining the strain resistance but also the physical factor (strain hardening of a porous body) plays a deci- sive role at compaction. However, in spite of a consid- erable step forward in the field of nanopowder compac- tion, the today’s more or less rigorous and self-consis- tent theories disagree with observations both quantitatively and qualitatively. In view of the aforesaid, we suggest a semiempiric approach [18] in terms of which the free parameters of the theory (hardening curve) are determined from experimental data for pulsed uniaxial compaction of a granulated medium (so-called compression adiabats). Radial pulsed magnetic compaction (RPMC) of nanop- owders, in the case of which the state of the granulated medium is unobservable, is simulated. Calculation results are compared with experimental data for the final state of compacts. 1. EXPERIMENTAL The characteristics of nanopowders that were sub- jected to RPMC are listed in the table. Nanopowder AM was obtained by electric explosion from Al + 1.3 wt%Mg alloy in the Institute of Electrophysics (Yekaterinburg, Ural Division, Russian Academy of Sciences) [19, 20]. To separate out coarse particles, the powders were suspended in isopropyl alcohol. After coarse particles had settled, the suspension was poured off and evaporated. The resulting dry residue was mechanically ground in an attrition mill. The bulk den- sity of the powder thus processed increases by five to six times, which greatly simplified its packing into a die before molding. Powder α-AM was prepared from Simulation of Radial Pulsed Magnetic Compaction of a Granulated Medium in a Quasi-Static Approximation G. Sh. Boltachev, N. B. Volkov, S. V. Dobrov, V. V. Ivanov, A. A. Nozdrin, and S. N. Paranin Institute of Electrophysics, Ural Division, Russian Academy of Sciences, ul. Amundsena 106, Yekaterinburg, 620016 Russia e-mail: grey@iep.uran.ru Received September 12, 2006 Abstract—Compression adiabats for alumina-based nanopowders are obtained experimentally, various condi- tions of pulsed magnetic cylindrically symmetric radial compaction of the nanopowders are tested, and the den- sity distribution in the compacted powders are measured. Using the compression adiabats obtained, quasi-static compaction of a granulated (porous) medium, which is considered to be compact, is simulated. The conditions of uniform and equilibrium compaction on a rigid rod are analyzed. The voidage distribution, stress tensor, and amount of accumulated deformation are calculated. The features of nanopowder compaction, specifically, the presence (absence) of voidage nonuniform radial distribution, are explained. PACS numbers: 81.05.Rm, 81.20.Ev, 81.07.Wx DOI: 10.1134/S106378420710009X SOLIDS