Analysis of In-Flight Oxidation During Reactive Spray Atomization and Deposition Processing of Aluminum

1999 ◽  
Vol 122 (1) ◽  
pp. 126-133 ◽  
Author(s):  
J.-P. Delplanque ◽  
E. J. Lavernia ◽  
R. H. Rangel
Keyword(s):  
Volume Fraction ◽  
Oxide Thickness ◽  
Progression Rate ◽  
Spray Atomization ◽  
One Dimensional ◽  
Spatially Resolved ◽  
Dimensional Equation ◽  
The One ◽  
Solid Liquid Interface ◽  
Solid Liquid

This work defines a model to predict the characteristics of materials processed using reactive spray atomization and deposition. The materials considered are aluminum alloys while target dispersoids are primarily oxides. These may be obtained by the reaction of oxygen-containing atomization gas mixtures with molten alloy droplets. Droplet position and velocity histories are obtained from the numerical solution of the one-dimensional equation of motion. The energy equation inside the droplet is solved numerically using finite differences to predict the spatially resolved temperature field. The solid/liquid interface progression rate is estimated using a power law while an oxidation rate expression based on the Mott-Cabrera theory is used for the oxide thickness. Such a model should prove very valuable in determining the parameters controlling the volume fraction and the size distribution of the dispersoids for various systems. [S0022-1481(00)02901-7]

scholarly journals High-precision measurement of velocity profiles in laser-created chlorine plasma

1995 ◽  
Vol 13 (4) ◽  
pp. 503-510 ◽  
Author(s):  
O. Renner ◽  
E. Krouský ◽  
T. Mißalla ◽  
E. Förster ◽  
G. Hölzer
Keyword(s):  
Spectral Lines ◽  
Plasma Parameters ◽  
High Precision Measurement ◽  
One Dimensional ◽  
Electron Temperature Gradient ◽  
Spatially Resolved ◽  
Doppler Shifts ◽  
Velocity Gradients ◽  
Marquardt Algorithm ◽  
The One

A vertical dispersion variant of the Johann spectrometer has been used to record the highresolution X-ray spectra of the chlorine He-like resonance line group emitted from lowradiance plasma. The emission profiles were measured at two observation angles and decomposed into single spectral lines by using a fit based on the Levenberg-Marquardt algorithm. The results of computerized analysis of the one-dimensional (1-D) spatially resolved spectra were used to evaluate the distribution of the main plasma parameters. The electron temperature gradient 7.5·104 eV cm-1 was computed by modeling the measured spectra with the collisional-radiative package RATION. The blowoff maximum velocities 4.2–6.1·107 cm s-1 and the velocity gradients 0.9–1.6·109 s-1 were determined from the Doppler shifts of individual spectral lines within their different spatial extent.

Effect of Heating Temperature on Microstructure of Directionally Solidified Ni-43Ti-7Al Alloy

2017 ◽  
Vol 898 ◽  
pp. 552-560 ◽  
Author(s):  
Lei Zhou ◽  
Li Jing Zheng ◽  
Hu Zhang
Keyword(s):  
Volume Fraction ◽  
Heating Temperature ◽  
Thermal Gradients ◽  
Directionally Solidified ◽  
Melt Structure ◽  
Cast Sample ◽  
The Stability ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Liquid Metal Cooling

By liquid metal cooling (LMC) process, the Ni-43Ti-7Al (at.%) alloy has been directionally solidified (DS) at different heating temperatures (1450°C, 1550°C, 1650°C) and a constant withdrawal rate of 100μm/s. The results showed that anomalous eutectic structures which consisted of Ti2Ni and TiNi phases were formed at the grain boundaries of as-cast sample and similar structures were also observed in the intercellular regions of DS samples. However, the microstructure changed from the equiaxial structure to the cellular structure due to the axial thermal gradients imposed. After DS, the NiTi and Ti2Ni phases preferentially grew along certain orientation, but the preferred crystallographic orientations of them changed as the heating temperature increased to 1650°C, which might be related to the change of melt structure. As expected, the volume fraction of Ti2Ni increased from 3.3% to 5.2% and the cellular spacing decreased from 47.8μm to 27.0μm as heating temperature increased. In addition, the stability of solid/liquid interface decreased, resulting from the coupling effects of G and ΔT- with the heating temperature increasing.

First Principles Simulations of SiC-Based Interfaces

2005 ◽  
Vol 483-485 ◽  
pp. 541-546 ◽  
Author(s):  
A. Catellani ◽  
G. Cicero ◽  
M.C. Righi ◽  
C.A. Pignedoli
Keyword(s):  
First Principles ◽  
Dislocation Core ◽  
Adsorbed Water ◽  
Water Molecules ◽  
Local Geometry ◽  
Microscopic Description ◽  
Semiconductor Interface ◽  
The One ◽  
Solid Liquid Interface ◽  
Solid Liquid

We review some recent investigations on prototypical SiC-based interfaces, as obtained from first-principles molecular dynamics. We discuss the interface with vacuum, and the role played by surface reconstruction in SiC homoepitaxy, and adatom diffusion. Then we move to the description of a buried, highly mismatched semiconductor interface, the one which occurs between SiC and Si, its natural substrate for growth: in this case, the mechanism governing the creation of a network of dislocations at the SiC/Si interface is presented, along with a microscopic description of the dislocation core. Finally, we describe a template solid/liquid interface, water on SiC: based on the predicted structure of SiC surfaces covered with water molecules, we propose (i) a way of nanopatterning cubic SiC(001) for the attachment of biomolecules and (ii) experiments to reveal the local geometry of adsorbed water.

Effect of Cooling Rate on the Microstructure and Precipitates of Directional Solidified 50W600 Non-oriented Silicon Steel

2013 ◽  
Vol 32 (6) ◽  
pp. 597-603
Author(s):  
Yong Wan ◽  
Wei-qing Chen ◽  
Shao-jie Wu
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Silicon Steel ◽  
Growth Region ◽  
State Growth ◽  
Average Size ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Relationship

AbstractThe microstructure, morphologies of precipitates in directional solidified 50W600 non-oriented silicon steel with three cooling rates (0.095, 0.33 and 4.28 °C/s) were investigated. The results showed that the morphology of solid-liquid interface evolved from cellular to cellular dendritic, and then to dendritic with an increase of cooling rate. The grain size of specimen in the steady-state growth region decreased with increasing cooling rate. The precipitates in the steel were mainly four types as follows: AlN, MnS, AlN-MnS and Fe3C. The amount and volume fraction of precipitates firstly increased and then decreased with increasing cooling rate, and reached maximum values in the specimen with a cooling rate of 0.76 °C/s. The average size of precipitates decreased gradually with increasing cooling rate. The relationship between the average size of precipitates and cooling rate was D = 75.762·R−0.190.

Large Amplitude Pulsatile Water Flow Across an Orifice

1975 ◽  
Vol 97 (1) ◽  
pp. 92-95 ◽  
Author(s):  
E. L. Yellin ◽  
C. S. Peskin
Keyword(s):  
Large Amplitude ◽  
Heart Valves ◽  
Equation Of Motion ◽  
Separated Flows ◽  
Prosthetic Heart Valves ◽  
One Dimensional ◽  
Water Flows ◽  
Lumped Parameter ◽  
Dimensional Equation ◽  
The One

The pressure-flow relations of large amplitude pulsatile water flows across an orifice have been investigated theoretically and experimentally. By retaining the unsteady term in the one-dimensional equation of motion, and by allowing the jet area to be a function of distance in the continuity equation, a lumped parameter relationship between pressure drop and flow has been developed which reflects the influence of inertia and dissipation. The results are applicable to the analysis of natural and prosthetic heart valves under normal and pathologic conditions. Within the physiologically possible conditions of frequency and flow rate, unsteady separated flows exhibit the same energy losses as comparable steady separated flows. Thus, the flow is quasi-steady, even when the waveforms and temporal relations indicate a significant inertial influence.

Effect of High Rotating Magnetic Field on the Solidified Structure of Al–7wt.%Si–1wt.%Fe Alloy

2013 ◽  
Vol 752 ◽  
pp. 57-65 ◽  
Author(s):  
András Roósz ◽  
Jenő Kovács ◽  
Arnold Rónaföldi ◽  
Árpád Kovács
Keyword(s):  
Magnetic Field ◽  
Interface Velocity ◽  
Longitudinal Section ◽  
Rotating Magnetic Field ◽  
Christmas Tree ◽  
Binary Eutectic ◽  
Si Content ◽  
The One ◽  
Solid Liquid Interface ◽  
Solid Liquid

Al–7wt.-% Si–1wt.-% Fe alloy was solidified unidirectionally in the Crystallizer with High Rotating Magnetic Field (CHRMF). The diameter of sample was 8 mm and its length was 120 mm. The parameters of solidification were as follows: solid/liquid interface velocity ~0.082 mm/s, temperature gradient 7+/-1 K/mm, magnetic induction 0 and 150 mT, frequency of magnetic field 0 and 50 Hz. The structure solidified without rotating magnetic field (RMF) showed a homogeneous, columnar dendritic one. The structure solidified by using magnetic stirring showed a dual periodicity. On the one hand, the branches of the “Christmas tree”-like structure known from the earlier experiments contained Al+Si binary eutectic. On the other hand, bands with higher Fe- and Si-content formed in the sample, which were at a larger distance from each other than the branches of the “Christmas tree” structure. The developed microstructure was analyzed by SEM with EDS. The average Si- and Fe-concentrations were measured on the longitudinal section at given places along the length of sample. Furthermore the Si- and the Fe-concentrations close to the bands and among the bands as well as the composition of the compound phases were determined.

scholarly journals Radial Imbibition in Paper under Temperature Differences

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 86
Author(s):  
Abel López-Villa ◽  
Abraham Medina ◽  
F. J. Higuera ◽  
Jonatan R. Mac Intyre ◽  
Carlos Alberto Perazzo ◽  
...  
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Porous Material ◽  
Radial Temperature ◽  
Temperature Variations ◽  
One Dimensional ◽  
Blotting Paper ◽  
Dimensional Equation ◽  
The One ◽  
Account Temperature

Spontaneous radial imbibition into thin circular samples of porous material when they have been subjected to radial temperature differences was analyzed theoretically and experimentally. The use of the Darcy equation allowed us to take into account temperature variations in the dynamic viscosity and surface tension in order to find the one-dimensional equation for the imbibition fronts. Experiments using blotting paper showed a good fit between the experimental data and theoretical profiles through the estimation of a single parameter.

Formation of Ferrite with Cr Equivalents and Solidification Rates in Mod. (9-12)Cr-1Mo Steels

2007 ◽  
Vol 124-126 ◽  
pp. 1497-1500
Author(s):  
Y.H. Kim ◽  
H.C. Kim ◽  
Yeon Gil Jung ◽  
J.H. Lee ◽  
B.H. Chi ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Volume Fraction ◽  
Solidification Rate ◽  
Liquid Interface ◽  
Solidification Microstructure ◽  
Composition Change ◽  
Heat Treated ◽  
Solid Liquid Interface ◽  
Solid Liquid

The influence of solidification rates and Cr equivalents on the formation of the ferrite was studied by directional solidification in mod. (9-12)Cr-1Mo steels. It was found that the volume fraction of ferrite increased as increasing Cr equivalent and solidification rate. The volume fraction of the ferrite showed much higher at low solidification rates with the planar or cellular interface than that at high solidification rates with the dendritic interface. The volume fraction of ferrite in solidification microstructure showed much higher than that in extruded and heat-treated alloys. It depends on not only solidification rate and Cr equivalent but also the solidification fraction. At low solidification rates, there occurs segregation because the solid/liquid interface was planar or cellular, and it makes composition change with solidification fractions. The formation of ferrite has been discussed with Cr equivalent and solidification rate.

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