scholarly journals An application of the interfacial wave theory of solidification

1991 ◽  
Vol 69 (11) ◽  
pp. 1326-1333
Author(s):  
Andonowati Andonowati
Keyword(s):  
Crystal Growth ◽  
Thermal Diffusivity ◽  
Solid State ◽  
Eigenvalue Problem ◽  
Stable State ◽  
Wave Theory ◽  
Interfacial Wave ◽  
Dendritic Crystal ◽  
Linear Eigenvalue Problem ◽  
Quantum Condition

In this paper we apply the interfacial wave theory of dendritic crystal growth to the case in which the thermal diffusivity constant and the specific heat of the liquid state are different from those of the solid state. The problem is formulated as a linear eigenvalue problem. A quantum condition for the eigenvalues is derived and a discrete set of possible solutions is found. The selection problem is solved using the global neutral stable state analysis proposed by the interfacial wave theory.

Interfacial wave theory of dendrite growth: global mode solution and quantum condition

1990 ◽  
Vol 68 (1) ◽  
pp. 58-66 ◽  
Author(s):  
Jian-Jun Xu
Keyword(s):  
Turning Point ◽  
Leading Edge ◽  
Wave Theory ◽  
Dendrite Growth ◽  
Interfacial Wave ◽  
Global Mode ◽  
Dendritic Crystal ◽  
Significant Step ◽  
Mode Solution ◽  
Quantum Condition

This paper is concerned with the global mode solutions of dendritic crystal growth. In this paper, we investigate the signal feed-back process at the leading edge of the dendrite tip and derive the global instability mechanism of the system on the basis of the previous results (Phys. Rev. A, 40, 1599 (1989); 40, 1609 (1989)). A global wave diagram of the system is explored, which we call WEASR (Wave emission at the turning point and signal reflections between the turning point and the leading edge of the tip). This WEASR mechanism determines a discrete set of unstable global modes for the system. The asymptotic solutions for these modes and the quantum condition for the corresponding eigenvalues are obtained. The discovery of the WEASR mechanism is quite a significant step leading to the understanding of instability phenomena in dendrite growth.

Montmorillonite Dendrites

1974 ◽  
Vol 32 ◽  
pp. 454-455
Author(s):  
Necip Güven ◽  
Rodney W. Pease
Keyword(s):  
Crystal Growth ◽  
Growth Mechanism ◽  
Growth Front ◽  
Morphological Features ◽  
Dendritic Crystal ◽  
Crystal Growth Mechanism

Morphological features of montmorillonite aggregates in a large number of samples suggest that they may be formed by a dendritic crystal growth mechanism (i.e., tree-like growth by branching of a growth front).

scholarly journals Growth of single crystals in the (Na1/2Bi1/2)TiO3–(Sr1–xCax)TiO3 system by solid state crystal growth

2021 ◽  
Author(s):  
Phan Gia Le ◽  
Huyen Tran Tran ◽  
Jong-Sook Lee ◽  
John G. Fisher ◽  
Hwang-Pill Kim ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Solid State ◽  
Single Crystal ◽  
Single Crystals ◽  
Piezoelectric Properties ◽  
Single Crystal Growth ◽  
Crystal Growth Rate ◽  
Large Strains ◽  
Growth Technique ◽  
The Matrix

AbstractCeramics based on (Na1/2B1/2)TiO3 are promising candidates for actuator applications because of large strains generated by an electric field-induced phase transition. For example, the (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 system exhibits a morphotropic phase boundary at x = 0.2–0.3, leading to high values of inverse piezoelectric constant d*33, which can be further improved by the use of single crystals. In our previous work, single crystals of (Na1/2B1/2)TiO3-SrTiO3 and (Na1/2B1/2)TiO3-CaTiO3 were grown by the solid state crystal growth technique. Growth in the (Na1/2B1/2)TiO3-SrTiO3 system was sluggish whereas the (Na1/2B1/2)TiO3-CaTiO3 single crystals grew well. In the present work, 0.8(Na1/2Bi1/2)TiO3-0.2(Sr1−xCax)TiO3 single crystals (with x = 0.0, 0.1, 0.2, 0.3, 0.4) were produced by the solid state crystal growth technique in an attempt to improve crystal growth rate. The dependence of mean matrix grain size, single crystal growth distance, and electrical properties on the Ca concentration was investigated in detail. These investigations indicated that at x = 0.3 the matrix grain growth was suppressed and the driving force for single crystal growth was enhanced. Replacing Sr with Ca increased the shoulder temperature Ts and temperature of maximum relative permittivity Tmax, causing a decrease in inverse piezoelectric properties and a change from normal to incipient ferroelectric behavior.

scholarly journals Synthesis and Thermal Properties of Cerium-Dysprosium Oxide

2016 ◽  
Vol 61 (2) ◽  
pp. 965-969 ◽  
Author(s):  
M. Mikuśkiewicz ◽  
M. Stopyra ◽  
G. Moskal
Keyword(s):  
Thermal Properties ◽  
Phase Composition ◽  
Thermal Diffusivity ◽  
Solid State ◽  
Cerium Oxide ◽  
Solid State Reaction ◽  
Synthesis And Characterization ◽  
Equimolar Ratio ◽  
Dysprosium Oxide

Abstract The paper presents results of investigation on synthesis and characterization of cerium-dysprosium oxide. The input powders - dysprosium oxide Dy2O3 and cerium oxide CeO2 - were mixed so as to obtain equimolar ratio of cations, milled in alcohol and synthesized via solid state reaction process at 1350°C under 15MPa in vacuum for 2h. The microstructure, phase composition and thermal properties were analyzed. The obtained material was multiphase. Non-stoichiometric compounds were identified. Thermal diffusivity of investigated material decreased in the temperature range of 25-1000°C from 0,71 to 0,45 mm2/s.

Solid-state mechanical alloying of plastic crystals

1997 ◽  
Vol 12 (12) ◽  
pp. 3254-3259 ◽  
Author(s):  
J. Font ◽  
J. Muntasell ◽  
E. Cesari ◽  
J. Pons
Keyword(s):  
Solid State ◽  
Binary System ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Room Temperature ◽  
Binary Systems ◽  
Solid Phase ◽  
Stable State ◽  
Plastic Crystals ◽  
Dsc Measurements

Ball milling has been used as a solid-state mechanical alloying technique in two binary systems of plastic crystals: neopentylglycol/pentaglycerin (NPG/PG), showing a partial solubility in the ordered phase, and 2-amino-2-methyl-1,3-propanediol/tris(hydroxymethyl) (AMP/TRIS) whose immiscibility in this ordered solid phase is almost total. For the AMP/TRIS system the stable state at room temperature was reached by milling. Contrarily, for NPG/PG, DSC measurements reveal that an annealing period is required after milling. These results have been compared with those of the pentaglycerin/pentaerythritol (PG/PE) binary system, previously studied, whose miscibility is total at room temperature.

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