Net shaping nanopowders with powerful ultrasonic action and methods of density distribution control

Abstract

Two methods of compacting dry poly-and nanodisperse powders into compacts of a complicated shape with uniform density distribution in the volume have been developed: pressing under powerful ultrasonic action and collector pressing by the control of friction forces redistribution. Experimental measuring and simulation of the process of deformation of a powder body by different methods show that in the case of ultrasonic pressing, the dispersion of the density distribution has decreased by 20%, and the relative differential of density along the pressing height has decreased by 35% as compared to the case of the conventional uniaxial pressing. Collector pressing allows reducing the dispersion of the density distribution (has decreased by a factor of 10), while the relative density differential along the green compact height has decreased by 60%.

The Comparison of the Characteristics of Displacement Isolines in the Cylindrical Green Compact under Ultrasonic Vibration

“…There are two methods to eliminate or reduce die wall friction forces for dry powder pressing process which allow pressing into complex shape compacts, with uniform density distribution in the bulk: pressing under a powerful ultrasonic action pressing and the collector pressing [10][11][12][13][14]. The former research presented density distribution for two dimensions, but this research shown density distribution of green compact in three dimensions of cross section to angle 150 degrees as show in figure 3-5.…”

“…The new die of conventional pressing is developed and patented by E.S. Dvilis and his group [10][11][12][13][14]. A collector pressing is a new die pressing that is called "Collector die" to make the green compact goes higher and uniform density in the volume.…”

“…E.S. Dvilis and his group also represented variety of research of ultrasonic vibrations in dry powder compaction [10][11][12][13][14].…”

EFFECT OF ULTRASONIC-ASSISTED COMPACTION ON DENSITY AND HARDNESS OF Cu-CNT NANOCOMPOSITES SINTERED BY CAPSULE-FREE HOT ISOSTATIC PRESSING

“…Recently, ultrasonic have been used to obtain better dispersion of a range of nanomaterials including CNTs [15][16][17]. Besides that, ultrasonic also emerged as the potential technique in material research and processing [18][19][20]. Khasanov and Dvilis [20] have showed that the better density and green strength of ZrO2-Y2O3 nanoparticles were obtained by the application of ultrasonic on the compaction step.…”

“…Besides that, ultrasonic also emerged as the potential technique in material research and processing [18][19][20]. Khasanov and Dvilis [20] have showed that the better density and green strength of ZrO2-Y2O3 nanoparticles were obtained by the application of ultrasonic on the compaction step. Considering the promising of ultrasonic, in this research, CuCNTs composites were produced by powder metallurgy, in which the technical ultrasonic had been used to assist in the compaction step.…”