Results 301 to 310 of about 30,563 (351)

Directional solidification of Ni3Al

Acta Metallurgica et Materialia, 1992
Abstract A nickel aluminide intermetallic material (IC-50) was directionally solidified under various growth rates utilizing a modified Bridgeman apparatus. The microstructural features of interest, namely: primary dentrite arm spacing (PDAS); secondary dendrite arm spacing (SDAS); and dendrite tip radius of curvature (ϱ) were measured as functions ...
H.K Kim, J.C Earthman, E.J Lavernia
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Directional Solidification

Applied Mechanics Reviews, 1990
The mechanical and electrical properties of crystals produced by a unidirectional process depend strongly on the temperature and flow field in the melt since these control the concentration of solute at the melt–crystal interface. The solute gradient there drives morphological instabilities that lead to cellular or dendritic interfaces.
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Microfaceting in directional solidification

Solid State Communications, 1994
Abstract When a thick impurity atom, like Sr, sticks to the solidification front, the latter tends to acquire a sawtooth profile in order to optimally accomodate the adsorbed monolayer. The effect is briefly described on thermodynamic and crystallographic grounds.
D. Camel, M. Papoular
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Wavelength Selection in Directional Solidification

Physical Review Letters, 1986
Cell-spacing selection in directional solidification is investigated. An integral equation describing steady-state cells in the limit where the solute diffusion length is much larger than the cell spacing is derived and solved numerically by Newton's method.
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Asymmetric cell in directional solidification

Physical Review E, 1993
An asymmetric cell is obtained numerically in the symmetric model of directional solidification. It bifurcates off the symmetric cell branch and has a zero transversal velocity. The bifurcation point is characterized by a parity breaking and a period doubling. The bifurcation diagram around the codimension-two point found in previous work [Phys. Rev. A
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Parametric control of microstructures in directional solidification

Physical Review A, 1992
We consider the effect of a periodic oscillation on the growth velocity of a liquid-solid interface during the directional solidification of a binary mixture. By using a different formalism for the description of the interface motion, we confirm the eventual stabilizing properties of the oscillation found in the analysis of Wheeler (J. Cryst. Growth 67,
, Pelce, , Rochwerger
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Directional solidification of the LiF - LiBaF3 eutectic

Materials Research Bulletin, 1988
Abstract The lamellar eutectic LiF - LiBaF 3 has been directionally solidified in different furnaces and special designed cartridges with growth rates between 3 and 60 mm/h and temperature gradients from 1.5 to 7°C/mm. The growth rates have been calculated from temperature measurements in the melt.
K. Recker, F. Wallrafen, K. Dupr�
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Testing shape selection in directional solidification

Physical Review B, 1987
We report results from an experiment on the directional solidification of pivalic acid. In addition to the usual cellular interface patterns, we observe a new, metastable dendritic form that can be interpreted in the light of recent ideas about pattern formation.
, Bechhoefer, , Libchaber
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Linear stability of directional solidification cells

Physical Review A, 1990
We formulate the problem of finding the stability spectrum of the cellular pattern seen in directional solidification. This leads to a nonlinear eigenvalue problem for an integro-differential operator. We solve this problem numerically and compare our results to those obtained by linearizing the eigenvalue problem by employing the quasistatic ...
, Kessler, , Levine
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Observation of front propagation in directional solidification

Physical Review A, 1992
We describe how spatial variation in the critical pulling speed for directional solidification is induced by breaking the symmetry about the pulling direction. This spatial variation results in localized nucleation of the Mullins-Sekerka instability. After nucleation, the instability spreads via front propagation.
, Gleeson, , Finn, , Cladis
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