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.

Effect of the High Rotating Magnetic Field (min. 30 mT) on the Unidirectionally Solidified Structure of Al7Si0.6Mg Alloy

2010 ◽  
Vol 649 ◽  
pp. 263-268 ◽  
Author(s):  
Jenő Kovács ◽  
Arnold Rónaföldi ◽  
András Roósz
Keyword(s):  
Magnetic Field ◽  
Cross Sections ◽  
Interface Velocity ◽  
Unidirectional Solidification ◽  
Rotating Magnetic Field ◽  
The Other ◽  
Basic Parameters ◽  
Solidification Parameters ◽  
Solid Liquid Interface ◽  
Solid Liquid

The topic of this paper is the unidirectional solidification of ternary Al7Si0.6Mg aluminium alloy in a rotating magnetic field of 30 -150 mT and the characterisation of effect of stirring on the solidified structure. During performing the experiment-series, one of the three solidification parameters (temperature gradient, solid/liquid interface velocity and magnetic induction) was continuously changed and the other two of them was kept on a constant value. The effect of these parameters on the developed structures was analysed during the evaluation of the experimental results. Moreover, the extent of Si-macrosegregation as well as the change of the secondary dendrite arm spacing were investigated on the longitudinal and cross-sections of samples as a function of the three basic parameters.

Transient Conductance Measurements During Pulsed Laser Annealing

1981 ◽  
Vol 4 ◽  
Author(s):  
M. O. Thompson ◽  
G. J. Galvin ◽  
J. W. Mayer ◽  
R. B. Hammond ◽  
N. Paulter ◽  
...  
Keyword(s):  
Single Crystal ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Laser Pulses ◽  
Molten Layer ◽  
Pulsed Laser Annealing ◽  
Complete Melting ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTMeasurements were made of the conductance of single crystal Au-doped Si and silicon-on-sapphire (SOS) during irradiation with 30 nsec ruby laser pulses. After the decay of the photoconductive response, the sample conductance is determined primarily by the thickness and conductivity of the molten layer. For the single crystal Au-doped Si, the solid-liquid interface velocity during recrystallization was determined from the current transient to be 2.5 m/sec for energy densities between 1.9 and 2.6 J/cm2, in close agreement with numerical simulations based on a thermal model of heat flow. SOS samples showed a strongly reduced photoconductive response, allowing the melt front to be observed also. For complete melting of a 0.4 μm Si layer, the regrowth velocity was 2.4 m/sec.

scholarly journals Solid-liquid interface morphology of white carbide eutectic during directional solidification

2017 ◽  
Vol 62 (1) ◽  
pp. 365-368 ◽  
Author(s):  
M. Trepczyńska-Łent
Keyword(s):  
Longitudinal Section ◽  
Argon Atmosphere ◽  
Liquid Interface ◽  
Interface Morphology ◽  
Directionally Solidified ◽  
Constant Temperature Gradient ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Scanning Electron ◽  
Made In

AbstractIn this paper the analysis of solid-liquid interface morphology in white carbide eutectic was made. In a vacuum Bridgman-type furnace, under an argon atmosphere, directionally solidified sample of Fe - C alloy was produced. The pulling rate was v = 125 μm/s (450 mm/h) and constant temperature gradient G = 33.5 K/mm. The microstructure of the sample was frozen. The microstructure of the sample was examined on the longitudinal section using an light microscope and scanning electron microscope.

scholarly journals Orientation and Velocity Dependence of the Nonequilibrium Partition Coefficient

1995 ◽  
Vol 398 ◽  
Author(s):  
K.M. Beatty ◽  
K.A. Jackson
Keyword(s):  
Monte Carlo ◽  
Diffusion Coefficient ◽  
Partition Coefficient ◽  
Interface Velocity ◽  
Velocity Dependence ◽  
Step Velocity ◽  
Equilibrium Partition ◽  
Equilibrium Partition Coefficient ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTMonte Carlo simulations based on a Spin-1 Ising Model for binary alloys have been used to investigate the non-equilibrium partition coefficient (kneq ) as a function of solid-liquid interface velocity and orientation. In simulations of Si with a second component kneq is greater in the [111] direction than the [100] direction in agreement with experimental results reported by Aziz et al. The simulated partition coefficient scales with the square of the step velocity divided by the diffusion coefficient of the secondary component in the liquid.

Solid–liquid interface velocity and diffusivity in laser-melt amorphous silicon

2000 ◽  
Vol 77 (15) ◽  
pp. 2337-2339 ◽  
Author(s):  
Luigi Brambilla ◽  
Luciano Colombo ◽  
Vittorio Rosato ◽  
Fabrizio Cleri
Keyword(s):  
Amorphous Silicon ◽  
Interface Velocity ◽  
Liquid Interface ◽  
Solid Liquid Interface ◽  
Solid Liquid

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.

Simulation of porosity reduction in random structures

1990 ◽  
Vol 5 (10) ◽  
pp. 2184-2196 ◽  
Author(s):  
P. B. Visscher ◽  
Joseph E. Cates
Keyword(s):  
Interface Velocity ◽  
Periodic Boundary Conditions ◽  
Pressure Solution ◽  
Forward Motion ◽  
Porosity Reduction ◽  
Random Structures ◽  
The Difference ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Rate Limiting

We describe an algorithm for computing the motion of a solid-liquid interface in 2D, which is applicable to geological pressure solution or to pressure sintering. The backward motion (toward the solid) of the interface is due to dissolution of the solid, and the forward motion (away from the solid) is due to the inverse process of reprecipitation. The interface velocity is assumed proportional to the difference between the solubility of the solid and the concentration of the solution. The former is dependent upon stress (the phenomenon of “pressure solution”), so our algorithm must also keep track of the stress. We use a Lagrangian grid, with constant-stress periodic boundary conditions. The method has been applied to porosity reduction in sandstone. It is applicable to other interface-following problems, such as freezing, if the motion is slow enough that heat transport is not rate-limiting.

Solidification and Epitaxial Re-Growth in Surface Nanostructuring With Laser-Assisted Scanning Tunneling Microscope

2005 ◽  
Author(s):  
Xinwei Wang ◽  
Yongfeng Lu
Keyword(s):  
Thermal Strain ◽  
Interface Velocity ◽  
Liquid Interface ◽  
Dynamics Simulation ◽  
Scanning Tunneling ◽  
Shear Stresses ◽  
Surface Nanostructuring ◽  
Long Time ◽  
Solid Liquid Interface ◽  
Solid Liquid

In this work, parallel molecular dynamics simulation is conducted to study the long-time (up to 2 ns) behavior of argon crystal in surface-nanostructuring with laser-assisted STM. A large system consisting of more than one hundred million atoms is explored. The study is focused on the solidification procedure after laser irradiation, which is driven by heat conduction in the material. Epitaxial re-growth is observed in the solidification. Atomic dislocation due to thermal strain-induced structural damages is observed as well in the epitaxial re-growth. During solidification, the liquid is featured with decaying normal compressive stresses and negligible shear stresses. Two functions are designed to capture the structure and distinguish the solid and liquid regions. These functions work well in terms of reflecting the crystallinity of the material and identifying the atomic dislocations. The study of the movement of the solid-liquid interface reveals an accelerating velocity in the order of 3~5 m/s. The spatial distribution of the solid-liquid interface velocity indicates a non-uniform epitaxial re-growth in space. The bottom of the liquid solidifies slower than that at the edge.

Sign in / Sign up

Export Citation Format

Share Document