ChemInform Abstract: Melting Equilibria of the Bi-Sr-Ca-Cu-O (BSCCO) System in Air: The Primary Crystallization Phase Field of the 2212 Phase and the Effect of Silver Addition.

ChemInform ◽  
2010 ◽  
Vol 29 (39) ◽  
pp. no-no
Author(s):  
W. K. WONG-NG ◽  
L. P. COOK ◽  
F. JIANG
Keyword(s):  
Phase Field ◽  
Primary Crystallization ◽  
Silver Addition ◽  
Bscco System

Effect of Ag on the primary phase field of the high-Tc (Bi,Pb)-2223 superconductor

2000 ◽  
Vol 15 (2) ◽  
pp. 296-305 ◽  
Author(s):  
W. Wong-Ng ◽  
L. P. Cook ◽  
W. Greenwood ◽  
A. Kearsley
Keyword(s):  
Phase Field ◽  
Volume Fraction ◽  
Primary Crystallization ◽  
Primary Phase ◽  
Crystallization Field ◽  
Primary Phase Field ◽  
Liquidus Data ◽  
Primary Crystallization Field ◽  
High Tc ◽  
Melt Composition

The subsolidus equilibria and the primary phase field (crystallization field) of the 110 K high-Tc (Bi,Pb)-2223 ([Bi,Pb]:Sr:Ca:Cu) phase have been determined in the presence of Ag under a 92.5% Ar/7.5% O2 atmosphere (volume fraction). A total of 29 six-phase volumes that include both the (Bi,Pb)-2223 and Ag phases was observed. These subsolidus volumes are similar to those observed without the presence of Ag. The compositional range of initial melts of these volumes (mole fraction basis) covers BiO1.5 from 5.6% to 25.3%, PbO from 0.4% to 13.8%, SrO from 8.4% to 31.9%, CaO from 12.2% to 33.3%, CuO from 21.7% to 40.9%, and AgO0.5 from 1.2% to 6.3%. Based on these data, the primary crystallization field for the (Bi,Pb)-2223 phase in the presence of Ag was constructed using the convex hull technique. A section through this “volume” was portrayed by holding the AgO0.5, SrO, and CaO components at the median value of the 29 compositions while allowing projection on the other three axes (BiO1.5, PbO, and CuO). The net effect of Ag on the melt composition is a reduction in the PbO concentration and an increase in the SrO content. Applications of the liquidus data are also discussed.

scholarly journals Phase-field modelling of microstructural evolution in primary crystallization

2009 ◽  
Vol 483 (1-2) ◽  
pp. 645-649 ◽  
Author(s):  
Pere Bruna ◽  
Eloi Pineda ◽  
Jose I. Rojas ◽  
Daniel Crespo
Keyword(s):  
Microstructural Evolution ◽  
Phase Field ◽  
Primary Crystallization ◽  
Field Modelling

A TEM study of the influence of microstructure on the superplastic behavior of a U-5.8 wt.% Nb alloy

1986 ◽  
Vol 44 ◽  
pp. 568-569
Author(s):  
G. Mackiewicz Ludtka
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Phase Field ◽  
Single Phase ◽  
Superplastic Behavior ◽  
Two Phase ◽  
Single Phase Field

Historically, metals exhibit superplasticity only while forming in a two-phase field because a two-phase microstructure helps ensure a fine, stable grain size. In the U-5.8 Nb alloy, superplastici ty exists for up to 2 h in the single phase field (γ1) at 670°C. This is above the equilibrium monotectoid temperature of 647°C. Utilizing dilatometry, the superplastic (SP) U-5.8 Nb alloy requires superheating to 658°C to initiate the α+γ2 → γ1 transformation at a heating rate of 1.5°C/s. Hence, the U-5.8 Nb alloy exhibits an anomolous superplastic behavior.

Modulated structures in (Bi,Pb)-Sr-Ca-Cu-O films

1990 ◽  
Vol 48 (4) ◽  
pp. 62-63
Author(s):  
Shozo Ikeda ◽  
Hirotoshi Hayakawa ◽  
Daniel R. Dietderich
Keyword(s):  
Rf Magnetron Sputtering ◽  
Potential Method ◽  
High Tc ◽  
Bscco System ◽  
Heat Treated ◽  
Modulated Structures ◽  
High Tc Phase ◽  
Deposited Films ◽  
Sputtering System

Pb addition makes easier to form the high Tc phase in the BSCCO system. However, Pb easily vaporized at high temperature. A controlled Pb potential method has been applied to grow the high Tc phase in films. Initially, films are deposited on cleaved MgO substrates using an rf magnetron sputtering system. These amorphous as-deposited films are heat treated in a sealed gold capsule along with a large pellet of Pb-added BSCCO. Details of the process and characterization of the films have been reported elsewhere (1). Films trated for 0.5h at 850° C contain mainly the low Tc phase with a small amount of the high Tc phase. Hawever, films treated for 3h at 850°C consist mainly of the high Tc phase. This film is superconductive with a Tc(zero) of 106K. The Pb/Bi ratio of the films, analysed by SEM- EDS, are 0.12 and 0.18 for heat tratment times of 0.5 and 3h, respectively. The present study investigates the modulated structures of these films using HREM.

Using phase field and third-order shear deformation theory to study the effect of cracks on free vibration of rectangular plates with varying thickness

2020 ◽  
Vol 71 (7) ◽  
pp. 853-867
Author(s):  
Phuc Pham Minh
Keyword(s):  
Free Vibration ◽  
Shear Deformation ◽  
Phase Field ◽  
Deformation Theory ◽  
Plate Thickness ◽  
Shear Deformation Theory ◽  
Rectangular Plates ◽  
Equilibrium Equations ◽  
Third Order ◽  
Free Vibration Frequency

The paper researches the free vibration of a rectangular plate with one or more cracks. The plate thickness varies along the x-axis with linear rules. Using Shi's third-order shear deformation theory and phase field theory to set up the equilibrium equations, which are solved by finite element methods. The frequency of free vibration plates is calculated and compared with the published articles, the agreement between the results is good. Then, the paper will examine the free vibration frequency of plate depending on the change of the plate thickness ratio, the length of cracks, the number of cracks, the location of cracks and different boundary conditions

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