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Displaying 26 - 37 of 37

Microsegregation in Peltier Interface Demarcation

July 1, 2000
Author(s)
Y Dabo, H N. Thi, Sam R. Coriell, Geoffrey B. McFadden, Q Li, B Billia
Experimental results on solute microsegregation induced by Peltier Interface Demarcation (PID) technique during directional solidification of Bi-1 wt % Sb alloys are presented. These data are compared with the results of numerical simulation and the theory

Convective and Morphological Instabilities During Crystal Growth

June 1, 2000
Author(s)
Sam R. Coriell, Geoffrey B. McFadden, B T. Murray
We have studied the effects of interface morphology on the dynamics of dendritic growth. The Ivantsov solution for an isothermal paraboloid of revolution growing into a pure, supercooled melt provides a relation between the bulk supercooling and a

On the Properties of Alpha/Alpha + Beta Diffusion Couples

January 1, 2000
Author(s)
William J. Boettinger, Sam R. Coriell, Carelyn E. Campbell, Geoffrey B. McFadden
The properties of diffusion couples in a ternary system are examined theoretically when one end member is composed of single-phase material (alpha) and the other end member is composed of two-phase material (α + Β). Using the model of Morral and co-workers

Solidification Microstructures: Recent Developments, Future Directions

January 1, 2000
Author(s)
William J. Boettinger, Sam R. Coriell, A L. Greer, A N. Karma, W Kurz, M Rappaz, R Trivedi
This review is intended to critically evaluate the latest status of solidification science and to discuss and propose future directions of research in this technologically important area. It is an updated version of the outcome of the 1998 Zermatt Workshop

Rapid Melting of Nb - 47 Mass % Ti: Effect of Heating Rate and Grain Size

September 8, 1999
Author(s)
William J. Boettinger, Daniel Josell, Sam R. Coriell, D Basak
The effect of heating rate and grain size on the melting behavior of Nb - 47 mass % Ti is measured. The experimental method uses rapid resistive self-heating of wire specimens at rates between 10(2 superscript) and 104 superscript) K/s and simultaneous

Shape Parameter for a Non-Axisymmetric Isothermal Dendrite

June 1, 1999
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, R F. Sekerka
In previous work, we found approximate solutions for paraboloids having perturbations with four-fold axial symmetry in order to model dendritic growth in cubic materials. These solutions provide self-consistent corrections through second order in a shape

Analytic Solution for a Non-Axisymmetric Isothermal Dendrite

March 1, 1999
Author(s)
Geoffrey B. McFadden, Sam R. Coriell, R F. Sekerka
The Ivantsov solution for an isothermal paraboloidal dendrite growing into a pure, undercooled melt provides a relation between the bulk undercooling and a dimensionless product, the Peclet number, of the growth velocity and tip radius of the dendrite

Effect of Heating Rate and Grain Size on the Melting Behavior of the Alloy Nb-47 Mass% Ti in Pulse-Heating Experiments

September 1, 1998
Author(s)
D Basak, William J. Boettinger, Daniel Josell, Sam R. Coriell, J L. McClure, Sitaraman Krishnan, A Cezairliyan
The effect of heating rate and grain size on the melting behavior of Nb-47 mass % Ti is measured and modeled. The experimental method uses rapid resistive self-heating of wire specimens at rates between -10 2 and -10 4 K/s and simultaneous measurement of

Interface Morphology During Crystal Growth: Effects of Anisotropy and Fluid Flow

August 12, 1998
Author(s)
Sam R. Coriell, B T. Murray, A A. Chernov, Geoffrey B. McFadden
We treat the effect of shear flows on the morphological stability of a crystal growing from solution by a step mechanism at a given constant velocity. We carry out some calculations for a shear flow that is sinusoidal in time.The interaction of fluid flow

Step Bunching: Influence of Impurities and Solution Flow

July 14, 1998
Author(s)
A A. Chernov, P G. Vekilov, Sam R. Coriell, B T. Murray, Geoffrey B. McFadden
Step bunching results in striations even at relatively early stages of its development and in inclusions of mother liquor at the later stages. Therefore, eliminating step bunching is crucial for high crystal perfection. The nature of step bunching

Multiple Similarity Solutions for Solidification and Melting

July 1, 1998
Author(s)
Sam R. Coriell, Geoffrey B. McFadden, R F. Sekerka, William J. Boettinger
We explore multiple one-dimensional similarity solutions during the solidification of a binary alloy and a pure material. The configuration is analogous that of a diffusion couple, for which multiple solutions in ternary alloys were discovered by Coates &