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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: In this article, the impact of casting parameters on the shear rate profiles experienced during deposition was evaluated via conventional flow analysis and computer simulations, and the influence of these parameters on line resolution/uniformity, printability, and as-cast component properties was studied using laser profilometry, optical microscopy, and scanning electron microscopy.
Abstract: Solid freeform fabrication of aqueous alumina–poly(vinyl alcohol) (Al2O3–PVA) gel-casting suspensions was conducted using a computer-controlled extrusion apparatus fitted with a two-nozzle delivery system. The impact of casting parameters on the shear rate profiles experienced during deposition was evaluated via conventional flow analysis and computer simulations. In addition, the influence of these parameters on line resolution/uniformity, printability, and as-cast component properties was studied using laser profilometry, optical microscopy, and scanning electron microscopy. Continuous printablity was achieved for tip diameters ranging from 0.254 to 1.370 mm for all mixing rates and suspension compositions studied. Printed lines were uniform with good edge definition, and line dimensions were independent of mixing rate for these process conditions. The Al2O3 volume fraction (φAl2O3) in the as-deposited layers depended on casting conditions and cross-linking agent concentration, where (φAl2O3 increased with decreased tip diameter and increased cross-linking agent concentration. The free-formed Al2O3 components exhibited uniform particle packing, with minimal macrodefects (e.g., slumping or staircasing) and no discernable microdefects (e.g., bubbles or cracking).
101 citations
TL;DR: In this paper, a model for the deposition of energy at powder particle surfaces during dynamic consolidation is presented, where the average energy flux incident on the surface of a powder particle is estimated to be E/τA where E is the specific energy deposited by the shock, τ is the shock rise time, and A the measured powder specific surface area.
Abstract: A model is presented for the deposition of energy at powder particle surfaces during dynamic consolidation. The average energy flux incident on the surface of a powder particle is estimated to be E/τA where E is the specific energy deposited by the shock, τ is the shock rise time, and A the measured powder specific surface area. This flux is assumed to be constant over the rise time of the shock, falling abruptly to zero for times longer than τ. Solution of the thermal transport equation subject to this boundary condition yields the thermal history within a powder particle having the area‐equivalent diameter D=6/ρ0A, where ρ0 is the solid density. The magnitude of the temperatures and the heating and cooling rates indicate likely material transformations. The penetration of a given isotherm provides an estimate of the volume fraction of material transformed. Good agreement is found between model calculations and measurements of the extent of local martensite formation in consolidated 4330V steel powder an...
101 citations
TL;DR: In this paper, different predictive models for the electrical conductivity of two-phase materials are assessed based on electrical conductivities measurements of metal matrix composites with non-conducting inclusions produced by gas pressure infiltration.
101 citations
TL;DR: The role of sphere size, volume fraction, relative humidity (RH), evaporation temperature and the final drying conditions on the film quality were investigated in this article, where they found that all those parameters must be taken into account in order to achieve highest quality for a given particle size.
101 citations
TL;DR: In this paper, the experimental results showed that the nanofluid viscosity in solid volume fraction of 0.85% and the temperature of 10 °C increased by 83%.
101 citations