CELL TO DENDRITE TRANSITION IN TIN BASE ALLOYS

1960 ◽  
Vol 38 (8) ◽  
pp. 1077-1088 ◽  
Author(s):  
T. S. Plaskett ◽  
W. C. Winegard
Keyword(s):  
Temperature Gradient ◽  
Distribution Coefficient ◽  
Cell Size ◽  
Dendritic Growth ◽  
Solute Concentration ◽  
Cellular Growth ◽  
First Approximation ◽  
High Concentrations ◽  
Solid Liquid Interface ◽  
Solid Liquid

The transition from cellular growth to dendritic growth was investigated for dilute binary alloys of zone-refined tin with lead, bismuth, and antimony in terms of the rate of growth R, the temperature gradient in the liquid ahead of the solid-liquid interface G, and the solute concentration C0. It was found that a previous relationship describing the transition for lead base alloys applied, at least to a first approximation, for the low solute concentration tin results. At the high concentrations of solute, however, it was necessary to introduce another variable, namely the cell size at transition dt. The transition relationships only applied for alloy systems with a distribution coefficient k0, less than unity. For systems with k0 > 1 (antimony in tin) a k0 < 1 was used which was equivalent to the k0 > 1. A method is described for determining this "equivalent k0".

GROWTH CONDITIONS FOR STABILITY OF A CELLULAR SOLID-LIQUID INTERFACE

1957 ◽  
Vol 35 (10) ◽  
pp. 1223-1227 ◽  
Author(s):  
E. L. Holmes ◽  
J. W. Rutter ◽  
W. C. Winegard
Keyword(s):  
Freezing Temperature ◽  
Growth Conditions ◽  
Solute Concentration ◽  
Critical Value ◽  
Liquid Interface ◽  
Cellular Solid ◽  
First Approximation ◽  
Comparison Of The Results ◽  
Solid Liquid Interface ◽  
Solid Liquid

Samples of zone-refined lead containing various amounts of silver as solute were solidified under well-controlled conditions to study the transition from cellular to dendritic freezing as a function of composition, speed of freezing, temperature gradient in the melt during freezing, and crystallographic orientation of the solidifying crystal. A comparison of the results of this investigation with those of Tiller and Rutter (1956) on alloys of tin in lead shows that to a first approximation the onset of dendritic freezing under any given growth conditions occurs at a critical value of the average solute concentration in the liquid at the solid–liquid interface, independent of whether the solute present is tin or silver.

Investigation on Mechanism of Faceted Cellular Array Growth in International Space Station

2012 ◽  
Vol 323-325 ◽  
pp. 533-537 ◽  
Author(s):  
Y. Inatomi ◽  
I. Yoshizaki ◽  
K. Sakata ◽  
T. Shimaoka ◽  
T. Sone ◽  
...  
Keyword(s):  
International Space Station ◽  
Space Station ◽  
Solute Concentration ◽  
Butyl Alcohol ◽  
Cellular Growth ◽  
International Space ◽  
Cellular Array ◽  
Microgravity Conditions ◽  
Solid Liquid

Anin situobservation experiment of faceted cellular growth was carried out using transparent organic alloy, salol -t-butyl alcohol, in microgravity conditions on the International Space Station. The temperature and solute concentration fields in the vicinity of the solid-liquid and the growth rate were simultaneously measured by microscopic interferometers.

Microstructural Perturbations in Directionally Solidified Al-In, Al-Bi and Zn-Bi Monotectic Alloys

1981 ◽  
Vol 12 ◽  
Author(s):  
B. Toloui ◽  
A. J. Macleod ◽  
D. D. Double
Keyword(s):  
Melting Point ◽  
Temperature Gradient ◽  
Growth Velocity ◽  
Liquid Interface ◽  
Liquid Region ◽  
Directionally Solidified ◽  
Lower Melting Point ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Oscillatory Instabilities

ABSTRACTStudies have been made of the microstructures developed in directionally solidified monotectic Al-In, Al-Bi and Zn-Bi alloys, as a function of growth velocity and temperature gradient. With increasing growth velocity and decreasing gradient the microstructures show transitions from regular rod-like arrangements of the lower melting point phase, through arrays of aligned droplets to coarse irregular droplet dispersions. Intermediate stages show rods with longitudinal shape perturbations of a classic Rayleigh-type instability. The changes are discussed in terms of oscillatory instabilities at the solid-liquid interface (enhanced by increasing growth velocity and decreasing temperature gradient) coupled with ripening effects in the solid + liquid region behind the interface.

Evolution of the Solidification Microstructure of Rheocast High Purity Aluminium

2012 ◽  
Vol 192-193 ◽  
pp. 109-115 ◽  
Author(s):  
Sarah George ◽  
Robert Knutsen
Keyword(s):  
High Purity ◽  
Liquid Interface ◽  
Cellular Growth ◽  
Solidification Mode ◽  
Purity Aluminium ◽  
High Purity Aluminium ◽  
Semi Solid ◽  
The Stability ◽  
Solid Liquid Interface ◽  
Solid Liquid

High purity aluminium has been successfully rheocast using the CSIR-RCS system combined with high pressure die casting. Analysis of the as-cast microstructure by SEM and EBSD revealed the presence of in-grain substructures. These morphological features show that the overall growth mode of the globular grains during rheocasting is planar, but the presence of these features indicates that the solidification mode is cellular at some stages during the slurry production process. Cellular solidification is associated with unstable growth at the solid-liquid interface and is initiated and exacerbated by solute gradients between the melt and the newly formed solid. This high purity alloy exhibits the same cellular growth, indicating that even minor solute variations have an effect on the stability of the solid-liquid interface and, hence, the mode of solidification during semi-solid rheocasting.

Temperature Measurement and Microstructure Control for Rene88DT Superalloy during Laser Rapid Forming

2007 ◽  
Vol 546-549 ◽  
pp. 2301-2306 ◽  
Author(s):  
Hua Tan ◽  
Jing Chen ◽  
Xin Lin ◽  
Xiao Ming Zhao ◽  
Wei Dong Huang
Keyword(s):  
Temperature Gradient ◽  
Temperature Measurement ◽  
Molten Pool ◽  
Liquid Interface ◽  
Solidification Velocity ◽  
Infrared Thermometer ◽  
Temperature Measurement System ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Laser Rapid Forming

Laser rapid forming (LRF) is a new manufacturing technology, which has been developed on the basis of multi-layer laser cladding. In the LRF process, the microstructure has important effects on the mechanical properties of the partsbut the control of microstructure is a problem. In this study, the influences of crystallography orientations of substrate and profile of solid/liquid interface on microstructure were discussed. Further, with the combining of the columnar to equiaxed transition (CET) model during alloy solidification, the growth law of microstructure of Rene88DT alloy was established. It has been found that the temperature gradient was lowest and the solidification velocity was greatest at the solid/liquid interface of the tail of molten pool, and hence the CET occurs easily at this position. The temperature measurement system of molten pool was developed by using a two-color infrared thermometer in this study. With the measurement of temperature gradient of the tail of molten pool by using a two-color infrared thermometer, the process parameters of laser multi-layer cladding were optimized. Finally, directional solidification even single crystal was achieved in laser multi-layer cladding.

Prediction of Solid-Liquid Interface Stability and Dendritic Growth in Multi-Component Alloys with Calphad Method

2005 ◽  
Vol 475-479 ◽  
pp. 2721-2724
Author(s):  
Rui Jie Zhang ◽  
Zhi He ◽  
Wan Qi Jie
Keyword(s):  
Experimental Data ◽  
Present Method ◽  
Dendritic Growth ◽  
Calphad Method ◽  
Liquid Interface ◽  
Interface Stability ◽  
Calculation Results ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Good Agreement

A method to predict the solid-liquid interface stability and the constrained dendrite growth of multi-component alloys was developed based on the Calphad method. The method was applied to several industrial Al-Si-Mg alloys, and the predicted results were compared with some former experimental data. The good agreement between the calculation results and the experimental data demonstrates the superiority of the present method to the classical one based on constant parameter assumptions.

scholarly journals Temperature Gradient and Heat Balance at the Solid-liquid Interface in CZ Silicon Growth.

Shinku ◽  
2000 ◽  
Vol 43 (5) ◽  
pp. 603-606
Author(s):  
Toshiyuki HIGASHINO ◽  
Katsuto TANAHASI ◽  
Naohisa INOUE ◽  
Atushi MORI
Keyword(s):  
Temperature Gradient ◽  
Heat Balance ◽  
Liquid Interface ◽  
Silicon Growth ◽  
Solid Liquid Interface ◽  
Solid Liquid

Phase-Field Microstructure Solidification of Al–2 wt% Si Alloys

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
J. B. Allen
Keyword(s):  
Directional Solidification ◽  
Phase Field ◽  
Maximum Concentration ◽  
Dendritic Growth ◽  
Interface Energy ◽  
Liquid Interface ◽  
Two Dimensional ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Dilute Alloy

In this work, we develop one- and two-dimensional phase-field simulations to approximate dendritic growth of a binary Al–2 wt% Si alloy. Simulations are performed for both isothermal as well as directional solidification. Anisotropic interface energies are included with fourfold symmetries, and the dilute alloy assumption is imposed. The isothermal results confirm the decrease in the maximum concentration for larger interface velocities as well as reveal the presence of parabolic, dendrite tips evolving along directions of maximum interface energy. The directional solidification results further confirm the formation of distinctive secondary dendritic arm structures that evolve at regular intervals along the unstable solid/liquid interface.

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