Selection of doublet cellular patterns in directional solidification through spatially periodic perturbations

1998 ◽  
Vol 58 (6) ◽  
pp. 7492-7506 ◽  
Author(s):  
W. Losert ◽  
D. A. Stillman ◽  
H. Z. Cummins ◽  
P. Kopczyński ◽  
W.-J. Rappel ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Periodic Perturbations ◽  
Spatially Periodic ◽  
Selection Of

Effects of the Interface Curvature and Dendrite Orientation in Directional Solidification of Bulk Transparent Alloys

2006 ◽  
Vol 508 ◽  
pp. 337-342 ◽  
Author(s):  
Cedric Weiss ◽  
Nathalie Bergeon ◽  
Nathalie Mangelinck-Noël ◽  
Bernard Billia
Keyword(s):  
Directional Solidification ◽  
Optical Methods ◽  
Fundamental Physics ◽  
Materials Engineering ◽  
Interface Curvature ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Selection Of

The properties of structural materials are to a large extent determined by the solid microstructure so that the understanding of the fundamental physics of microstructure formation is critical in the field of materials engineering. A directional solidification facility dedicated to the characterization of solid-liquid interface morphology by means of optical methods has been developed by CNES in the frame of the DECLIC project. This device enables in situ and real time studies on bulk transparent materials. The aim of the project is to perform experiments in microgravity to eliminate the complex couplings between solidification and convection and to get reliable benchmark data to validate and calibrate theoretical modeling and numerical simulations. Presently, ground experiments are performed to finalize the design and the experimental procedures and to guarantee the accuracy of the measurements. These experiments also provide reference data for the study of solidification microstructure dynamics in the presence of buoyancy-driven natural convection. Recent progress is presented concerning the control of the interface shape (critical for pattern analysis), the selection of single crystal of defined orientation (critical for dendritic growth) and the analysis of the dendrite shape.

scholarly journals Propagative selection of tilted array patterns in directional solidification

2018 ◽  
Vol 2 (5) ◽  
Author(s):  
Younggil Song ◽  
Silvère Akamatsu ◽  
Sabine Bottin-Rousseau ◽  
Alain Karma
Keyword(s):  
Directional Solidification ◽  
Selection Of

scholarly journals Investigation of Microstructure Evolution and Phase Selection of Peritectic Cuce Alloy During High-Temperature Gradient Directional Solidification

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 911
Author(s):  
Yiku Xu ◽  
Zhaohao Huang ◽  
Yongnan Chen ◽  
Junxia Xiao ◽  
Jianmin Hao ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Primary Dendrite ◽  
Primary Phase ◽  
Withdrawal Rate ◽  
Compressive Property ◽  
Directionally Solidified ◽  
Phase Selection ◽  
Coupled Growth ◽  
Selection Of

In this work, a CuCe alloy was prepared using a directional solidification method at a series of withdrawal rates of 100, 25, 10, 8, and 5 μm/s. We found that the primary phase microstructure transforms from cellular crystals to cellular peritectic coupled growth and eventually, changes into dendrites as the withdrawal rate increases. The phase constituents in the directionally solidified samples were confirmed to be Cu2Ce, CuCe, and CuCe + Ce eutectics. The primary dendrite spacing was significantly refined with an increasing withdrawal rate, resulting in higher compressive strength and strain. Moreover, the cellular peritectic coupled growth at 10 μm/s further strengthened the alloy, with its compressive property reaching the maximum value of 266 MPa. Directional solidification was proven to be an impactful method to enhance the mechanical properties and produce well-aligned in situ composites in peritectic systems.

Oscillatory Instabilities in Cellular Solidification

1990 ◽  
Vol 43 (5S) ◽  
pp. S56-S58 ◽  
Author(s):  
K. Brattkus
Keyword(s):  
Directional Solidification ◽  
Absolute Stability ◽  
Symmetric Model ◽  
Solid Diffusion ◽  
Long Wave ◽  
Spatially Periodic ◽  
The Stability ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Oscillatory Instabilities

We adapt the recent derivation of a long-wave evolution equation for a solid-liquid interface undergoing directional solidification near the limit of absolute stability to the case of a symmetric model that includes solid diffusion. The stability of steady and spatially periodic solutions are investigated and it is found that these cellular solutions are subject to an oscillatory instability with twice the wavenumber of the underlying pattern. We discuss this instability in the context of experiments on the directional solidification of nematic liquid crystals.

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