Stability of cellular patterns in directional solidification
نویسندگان
چکیده
منابع مشابه
Cellular instabilities in directional solidification
2014 We have studied the morphology of the solid-liquid interface during the directional solidification of thin (5-150 03BCm) samples of a dilute binary mixture (CBr4/~ 0.1 % Br2) . Above a critical pulling speed, for a given temperature gradient and solute concentration, the interface, initially planar, breaks down into a periodic cellular pattern. The bifurcation from a planar to a cellular s...
متن کاملCritical Role of Crystalline Anisotropy in the Stability of Cellular Array Structures in Directional Solidification.
We calculate numerically the full Floquet-Bloch stability spectrum of cellular array structures in a symmetric model of directional solidification. Our results demonstrate that crystalline anisotropy critically influences the stability of these structures. Without anisotropy, the stability balloon of cells in the plane of wave number and velocity closes near the onset of morphological instabili...
متن کاملStability and shapes of cellular profiles in directional solidification: expansion and matching methods
Ideas based on constitutional supercooling suggest that the periodic steady state cellular patterns seen in the directional solidification of systems with small partition coefficient may be unstable if the impurity concentration in the melt just in front of the tips falls into the two phase (miscibility gap) region of the phase diagram. This gives a simple stability criterion relating the posit...
متن کاملExperimental observation of oscillatory cellular patterns in three-dimensional directional solidification.
We present a detailed analysis of oscillatory modes during three-dimensional cellular growth in a diffusive transport regime. We ground our analysis primarily on in situ observations of directional solidification experiments of a transparent succinonitrile 0.24wt% camphor alloy performed in microgravity conditions onboard the International Space Station. This study completes our previous report...
متن کاملSelection of doublet cellular patterns in directional solidification through spatially periodic perturbations
Pattern formation at the solid-liquid interface of a growing crystal was studied in directional solidification using a perturbation technique. We analyzed both experimentally and numerically the stability range and dynamical selection of cellular arrays of ‘‘doublets’’ with asymmetric tip shapes, separated by alternate deep and shallow grooves. Applying an initial periodic perturbation of arbit...
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ژورنال
عنوان ژورنال: Physical Review A
سال: 1990
ISSN: 1050-2947,1094-1622
DOI: 10.1103/physreva.42.5056