scholarly journals Diffusion in Copper/Cobalt Systems under High Magnetic Fields

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3104
Author(s):  
Zhiwei Zhang ◽  
Xiang Zhao ◽  
Sadahiro Tsurekawa
Keyword(s):  
Magnetic Field ◽  
Grain Boundary ◽  
Diffusion Couple ◽  
High Magnetic Field ◽  
Vacancy Concentration ◽  
Frequency Factor ◽  
Magnetic Field Direction ◽  
Enhanced Diffusion ◽  
Electron Probe Micro Analyzer ◽  
Diffusion Entropy

Comprehensive research on a high magnetic field’s effect on diffusion is lacking; hence, this study investigates the effect of the magnetization of such a field on diffusion using a copper/cobalt diffusion couple in the diamagnetic/ferromagnetic states, respectively. The diffusion couple was formed using explosive welding to avoid diffusion during manufacturing. The diffusion couple annealed within a temperature range of 1165 –1265 K under a 0–6-T high magnetic field. The angle between the diffusion and magnetic field directions was set as 0° and then 180°. The penetration profiles of cobalt volume diffusion in the copper and grain-boundary diffusion of copper in cobalt were constructed using an electron probe micro analyzer. The high magnetic field increased the volume diffusivity of cobalt in copper, but had no evident effect on the grain-boundary diffusivity of copper in cobalt, irrespective of the magnetic field direction. An Arrhenius plot of the cobalt volume diffusivity in copper demonstrated that the applied high magnetic field enhanced diffusion by changing the frequency factor rather than the activation energy; this can be attributed to the increased diffusion entropy caused by changing the vacancy concentration, which resulted from the introduction of magnetization under a high magnetic field.

Crystallographic effect of a high magnetic field on a solidified hypoeutectic Zn–Al alloy

2014 ◽  
Vol 47 (2) ◽  
pp. 606-612 ◽  
Author(s):  
Lei Li ◽  
Zongbin Li ◽  
Yudong Zhang ◽  
Claude Esling ◽  
Haitao Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Orientation Relationship ◽  
High Magnetic Field ◽  
Resistance Force ◽  
Al Alloy ◽  
Magnetic Field Direction ◽  
Continuous Growth ◽  
Β Phase ◽  
Crystallographic Orientation Relationship ◽  
Orientation Modification

Hypoeutectic Zn–4.45 wt% Al solidified under a high magnetic field was investigated crystallographically. With the field, the primary zinc-rich β phase is distributed homogeneously and orients with thecaxis perpendicular to the magnetic field direction. These results are attributed to the magnetic viscosity resistance force and the magnetocrystalline anisotropy of zinc, respectively. The orientation modification also leads to a preferential alignment of the flat-shaped primary β dendrites. Furthermore, with the field, the eutectic β phase shows an orientation character similar to that of the primary β phase. This arises from its continuous growth with the primary β phase. In addition, a specific crystallographic orientation relationship ({0001}β||{111}α, 〈1\overline 210〉β||〈110〉α) exists in some of the eutectics (between the eutectic zinc-rich β and aluminium-rich α phases). However, this orientation relationship is related to the distribution of primary β dendrites, which originates from the independent nucleation of the pseudo-primary α phase attached to the primary β dendrites.

Effects of High Magnetic Field Heat Treatment on the Microstructure of Fe-0.76%C Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 863-869 ◽  
Author(s):  
Ming Long Gong ◽  
Xiang Zhao ◽  
Chang Shu He ◽  
J.Y. Song ◽  
Liang Zuo
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Lamellar Spacing ◽  
Field Direction ◽  
Magnetic Field Direction ◽  
High Carbon Content ◽  
Proeutectoid Ferrite ◽  
Alloy Microstructure ◽  
And Shifts ◽  
The Magnetic Field

The present studies are to investigate the microstructure features during transformation from austenite to ferrite without and with magnetic field on Fe-0.76%C alloy. It is found that the area fraction and numbers of proeutectoid ferrite grain as well as the lamellar spacing of pearlite in Fe-0.76%C alloy increased considerably with the increase of magnetic field intensity. The reason is that, the magnetic field increases the driving force of proeutectoid ferrite nuclei and shifts the eutectoid point to the side of high carbon content and high temperature, which increases the starting-temperature of the transformation from austenite to ferrite. The proeutectoid ferrite grains are elongated along the magnetic field direction, which can be explained as follows: the proeutectoid ferrite becomes the magnetic dipolar under high magnetic field, and then the polarized austenite atoms are much easier to diffuse into ferrite grains along the magnetic field direction. Key words: high magnetic field; Fe-0.76%C alloy; microstructure

Formation of c-Axis Aligned Hydroxyapatite Sheet by Simultaneous Imposition of High Magnetic Field and Mold Rotation During Slip Casting Process

2006 ◽  
Vol 309-311 ◽  
pp. 53-56 ◽  
Author(s):  
Jun Akiyama ◽  
Masami Hashimoto ◽  
Hiroaki Takadama ◽  
Fukue Nagata ◽  
Yoshiyuki Yokogawa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Materials ◽  
High Magnetic Field ◽  
Static Magnetic Field ◽  
Slip Casting ◽  
Casting Process ◽  
Field Direction ◽  
Magnetic Field Direction ◽  
Hydroxyapatite Crystal ◽  
Crystal Alignment

A high magnetic field is a useful tool to control the crystal alignment of non-magnetic materials such as ceramics and polymers. In the case of Hydroxyapatite crystal, the a,b-axis is aligned parallel to the direction of an imposed magnetic field. This fact implies that the alignment of the c-axis is not controllable only using a high static magnetic field due to the freedom of the c-axis in a plane perpendicular to a magnetic field direction. In this study, a high static magnetic field and mold rotation was simultaneously so applied during a slip casting process as to align the c-axis of HAp poly crystals.

Sintering Shrinkage Anisotropy of Spherical Alumina Powder Compacts with Particle Orientation

2007 ◽  
Vol 334-335 ◽  
pp. 293-296 ◽  
Author(s):  
Yan Chun Liu ◽  
An Ze Shui ◽  
Xue Tan Ren ◽  
Ling Ke Zeng
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Field Direction ◽  
Particle Orientation ◽  
Alumina Powder ◽  
Magnetic Field Direction ◽  
Axis Direction ◽  
Powder Compacts ◽  
Sintering Shrinkage ◽  
Spherical Alumina

Spherical alumina powder and dispersant were mixed with distilled and deionized water, and ball milled to make alumina slurry. The slurry was dried in a high magnetic field to make a compact. Subsequently, the compact was cold-isostatic-pressed (CIP) to enhance the homogeneity in particle packing density. Anisotropy of shrinkage during sintering was examined for the alumina compacts in detail. Particle orientation existed in the spherical alumina powder compacts prepared in 10T, and made them shrink anisotropically during sintering. Sintering shrinkage was larger in the direction parallel to magnetic field direction (i.e., the c-axis direction of alumina crystal) than that in its perpendicular direction. The particle orientation structure in the compacts was confirmed with the immersion liquid method of polarized light microscope, and the grain alignment structure in the sintered bodies was also observed with X-ray diffraction, the c-plane was perpendicular to the magnetic field direction. On the other hand, isotropic sintering shrinkage occurred in the spherical alumina powder compacts prepared in 0T, which did not hold the particle orientation. The experimental results indicate that sintering shrinkage of spherical alumina powder compact depends on alumina crystal axis direction. Origin of the sintering shrinkage anisotropy for the spherical alumina powder compacts can be attributed to the particle orientation caused by high magnetic field.

Grain boundary motion and grain growth in zinc in a high magnetic field

2013 ◽  
Vol 49 (11) ◽  
pp. 3875-3884 ◽  
Author(s):  
Dmitri A. Molodov ◽  
Christoph Günster ◽  
Günter Gottstein
Keyword(s):  
Magnetic Field ◽  
Grain Boundary ◽  
Grain Growth ◽  
High Magnetic Field ◽  
Boundary Motion ◽  
Grain Boundary Motion

Intermediate Phase Growth of Mg-Al Diffusion Couple under a Strong Static Magnetic Field

2007 ◽  
Vol 546-549 ◽  
pp. 491-494 ◽  
Author(s):  
Jie Dong ◽  
Z.F. Li ◽  
Xiao Qin Zeng ◽  
Wen Jiang Ding
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Diffusion Couple ◽  
Static Magnetic Field ◽  
Intermediate Phase ◽  
Thickness Measurement ◽  
Magnetic Field Direction ◽  
Diffusion Couples ◽  
Phase Growth ◽  
Intermediate Phases

Intermediate phase growth in Mg-Al diffusion couples were studied with different intensity of a strong static magnetic field from 0 to 10 Tesla. Thickness measurement of the intermediate phases (Mg17Al12 and Al3Mg2) shows that with the increasing of magnetic field intensity, the growth rate of both intermediate phases is retarded. The decrease of the phase growth rate is ascribed to the suppressed Al, Mg atom interdiffusion in the diffusion couple under the static magnetic field. It is also found that the orientation relationship between couple interface and magnetic field direction has no influence on the growth of intermediate phases.

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