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Volume fraction

About: Volume fraction is a research topic. Over the lifetime, 16312 publications have been published within this topic receiving 374181 citations.


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TL;DR: It is demonstrated that fluid inertia causes a strong microstructure anisotropy that results in the formation of a shadow region with no relative flux of particles that can be explained as an increase of the effective volume fraction when considering the dynamically excluded volume due to these shadow regions.
Abstract: Shear thickening appears as an increase of the viscosity of a dense suspension with the shear rate, sometimes sudden and violent at high volume fraction. Its origin for noncolloidal suspension with non-negligible inertial effects is still debated. Here we consider a simple shear flow and demonstrate that fluid inertia causes a strong microstructure anisotropy that results in the formation of a shadow region with no relative flux of particles. We show that shear thickening at finite inertia can be explained as an increase of the effective volume fraction when considering the dynamically excluded volume due to these shadow regions.

95 citations

Journal ArticleDOI
TL;DR: In this paper, the crystal structure, microstructure, microhardness and compression mechanical properties of AlxNbTiVZr (x = 0, 05, 1, 15) high entropy alloy were examined.
Abstract: The crystal structure, microstructure, microhardness and compression mechanical properties of AlxNbTiVZr (x = 0, 05, 1, 15) high entropy alloy were examined In the as solidified conditions, the alloys consisted from bcc matrix and C14 Laves phase After homogenisation, the NbTiVZr alloy was bcc solid solution, whereas in Al containing alloys, C14 Laves phase and Zr2Al particles were found in the bcc matrix Volume fraction of second phase increased with Al concentration Increase in Al content results in gradual decrease in density of the alloys from 649 g cm− 3 of the NbTiVZr to 555 g cm− 3 of the Al15NbTiVZr alloy The microhardness of the alloys was higher in the alloys with higher Al content and was generally proportional to the volume fraction of second phase particles The compression yield strength of the alloys was of 960–1320 MPa, and NbTiVZr alloy was stronger than Al containing alloys The ductility of the alloys gradually decreased with increase in Al content The factors determi

95 citations

Journal ArticleDOI
TL;DR: The mechanical properties of solid-state sintered 93W•5.6Ni•1.4Fe tungsten heavy alloys fabricated by mechanical alloying were investigated in this paper.
Abstract: The mechanical properties of solid-state sintered 93W‐5.6Ni‐1.4Fe tungsten heavy alloys fabricated by mechanical alloying were investigated. Blended W, Ni and Fe powders were mechanically alloyed in a tumbler ball mill at a milling speed of 75 rpm employing a ball-to-powder ratio of 20:1 and a ball filling ratio of 15%. A nanocrystalline size of 16 nm and fine lamellar spacings of 0.2 mm were obtained in mechanically alloyed powders at a steady state milling stage. Mechanically alloyed powders were consolidated into green compacts and solid-state sintered at 1300°C fo r1hi n ahydrogen atmosphere. The alloys sintered from mechanically alloyed powders showed fine tungsten particles (about 3 mm in diameter) and a relative density above 99%. The volume fraction of the matrix phase was 11% and the tungsten:tungsten contiguity was determined to be 0.74. The alloys exhibited high yield strengths (about 1100 MPa) due to their fine microstructures, but exhibited reduced elongation and impact energy due to a large area fraction of tungsten:tungsten boundaries and the low volume fraction of matrix phase. © 2000 Elsevier Science S.A. All rights reserved.

95 citations

Journal ArticleDOI
TL;DR: In this paper, the fractional effect of porosity and clay on the velocities for dry clastic silicate rocks was described (above 120 MPa) by u = A - B# - CCluy, where v is the velocity of the P-wave or S-wave, # is the volume fraction of pores, and Clay is the volumetric fraction of clay.
Abstract: SUMMARY For clastic silicate rocks sampled from a Rotliegendes well core the velocities up and us were obtained at 10 pressures up to 300MPa using a pulse-transmission technique. The porosities of all rocks (57 sandstones, 26 siltstones, five claystones) ranged from 0.01 and 0.15 by volume fraction, and the clay content varied from less than 0.01 to 0.88 by volume fraction. Both velocities increase with pressure. In the low-pressure range the rate of increase is large, non-linear and is greater for up than for us. Above 120 MPa both velocities increase linearly. Velocities, porosity, and clay content were fitted by least-squares regression for pressures of 8, 24, 60, 120, 200, and 300 MPa. The fractional effect of porosity and clay on the velocities for dry clastic silicate rocks can be described (above 120 MPa) by u = A - B# - CCluy, where v is the velocity of the P-wave or S-wave, # is the volume fraction of pores, and Clay is the volume fraction of clay. From this it is possible to obtain pressure-dependent velocity functions u = a +pb - c exp (-dp), where u is the crack-free velocity, linear in porosity and clay, b is the velocity slope under high pressure, u - c is the zero-pressure velocity, and d is related to closure of cracks.

95 citations

Journal ArticleDOI
TL;DR: In this article, the electrical and magnetic properties of composite materials prepared by incorporating various nickel-based fillers of different shapes into polyethylene were investigated, and composite samples were characterized in terms of their volume resistivity, dielectric constant, and magnetic permeability values.
Abstract: Electrical and magnetic properties of composite materials prepared by incorporating various nickel-based fillers of different shapes into polyethylene were investigated. The fillers used were nickel powders, nickel filamentary powders, nickel flakes, and nickel-coated graphite fibers. The particle-size distributions of the fillers were determined both before and after the processing of the composite samples. A wide range of filler volume fractions were used. In some cases, the volume fraction approached the maximum packing fraction of the solid phase to significantly exceed the percolation threshold. The composite samples were characterized in terms of their volume resistivity, dielectric constant, and magnetic permeability values. Filler particles of asymmetric shapes were very effective in terms of altering the electrical properties of the composite samples. At the highest loading levels of the nickel fillers, the volume resistivity values of the composites decreased by more than 17 orders of magnitude. AT such high filler concentrations, the dielectric constant values of the composite samples increased considerably, to values that were greater than 1,000. The permeability values of the samples increased linearly with the volume fraction of the nickel filler and were insensitive to the shape of the fillers. The highest relative permeability value measured was 5.8 for compositesmore » with 67% by volume of nickel powder.« less

95 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023965
20222,020
2021744
2020736
2019786
2018696