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The distribution maps of cube-oriented grains in the surface of (a) 23T 17R, (b) 25T 17R and (c) 27T 17R, ˆnally annealed at 300° C for 60, 180 and 600 s.
Source publication
The present study was carried out to clarify the effect of condition of thermo-mechanical treatment (partial annealing and additional rolling) on behavior of cube texture in high purity aluminum foils for electrolytic capacitor. Foils were partially annealed at 503, 523 and 543 K and additionally rolled to 12, 17 and 22% reduction. They were finall...
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Homogeneous nucleation from aluminum (Al) melt was investigated by million-atom molecular dynamics (MD) simulations utilizing the second nearest neighbor modified embedded atom method (MEAM) potentials. The natural spontaneous homogenous nucleation from the Al melt was produced without any influence of pressure, free surface effects and impurities....
Citations
... Many studies concerned with a formation of Cube texture were performed widely in the production process from the hot rolled sheets to the final annealed foils up to date. [1][2][3][4][5][6][7][8][9][10][11] It was considered in the previous studies that Cube-oriented nuclei formed during the hot rolling or cold rolling, they became stable grains in partial annealing process, and in final annealing process, the Cube grains were able to grow preferentially with strain-induced grain boundary migration (SIBM) driven by difference in stored energy introduced by additional rolling process. It was mentioned that Cube grains were less affected than other oriented grains by deformation of additional rolling [12][13][14] or were able to recover earlier than other oriented ones. ...
Continuous cyclic bending (CCB) has been proposed as a useful straining technique to produce the high strain on the surface layers and the lower strain in the central layer of the sheet. A pure aluminum sheet is worked by the CCB using the "Roll traveling device" and "Roll driven machine". It is found that a sharp Cub, orientation is formed by the CCB and subsequent annealing in the pure aluminum sheet. Influences of the CCB/annealing process parameters such as partial or final annealing temperature, strain inside grains and repeating effect, on the Cube sharpening are investigated. The sharper Cube orientation is obtained for the higher temperature of the final annealing after the roll traveling device CCB. While a considerably strong Cube texture appears after one routine of the roll driven machine CCB/773 K-3.6 ks, the texture is weakened after two routines repeated to change into a random texture. The 10 Pass and 20 Pass CCBs with a comparatively low degree of working before partial annealing lead to a high Cube fraction more than 60%.
High-purity (99.99 wt.%) Al containing 50 wt. ppm Cu was cold rolled to 98 % reduction in thickness and annealed by varying the heating rate of annealing and annealing cycles. Textures developed at various stages of annealing were investigated with the orientation distribution function analysis. The observed results were compared with those obtained on standard high purity (99.99 wt.%) Al without Cu addition. In slow heating rate annealing, it was found that in high purity Al the addition of 50 wt.ppm Cu significantly enhanced the development of {100}〈001〉 recrystallization textures. Intensities of {100}〈001〉 developed in high purity Al with 50 wt. ppm Cu were about twice as high as those observed in high purity Al without Cu addition. {123}〈634〉 R orientations were completely eliminated by the addition of 50 wt. ppm Cu. In rapid heating annealing, on the other hand, annealing at temperatures above 325°C resulted in the formation of very coarse recrystallized grains with weak {100}〈001〉 recrystallization textures irrespective of Cu content. Such grain coarsening could be suppressed by pre-annealing at temperatures between 225 and 300°C. In the specimens subjected to this pre-annealing, strong {100}〈001〉 recrystallization textures could be obtained, even if they were annealed with a rapid heating rate in final annealing.
Pure copper sheets were heavily deformed up to equivalent strain of 4.8 by the accumulative roll-bonding (ARB) processed and then annealed. The ARB processed copper showed the ultra-fine grained microstructure which consisted of relatively equiaxed grains having grain thickness of about 0.2 mu m. The DSC measurement of the ARB processed specimens revealed that the recrystallization temperature significantly decreased with increasing the number of the ARB cycles. The stored energy did not increase so much at later stage of ARB, which corresponded with the change in microstructure. The recystallization behavior of the ARB processed copper was governed by discontinuous recrystallization characterized by nucleation and growth process. Remarkable development of cube texture ({100} [001]) was found in the specimen deformed to the equivalent strain of 3.2 or larger and then annealed. The concentration of the cube recrystallization texture depended on the number of ARB cycles.
It is well known that a sharp Cube texture is developed for the producing process of a Pure aluminum foil for capacitors. The orientation analysis using scanning electron microscopy/electron backscattered diffraction pattern (SEM/EBSP) method has been performed on the transverse direction (TD) sections of partially annealed (PAed) and additionally rolled (ARed) foils through the thickness in order to reveal how Cube-oriented grains have advantages for growth in comparison with the other grains with orientation components of rolling texture. Samples were annealed repeatedly with increasing the temperature in a vacuum. The Cube grains were distributed throughout foil thickness homogeneously in the PAed and ARed foils. The main mechanism of preferential growth of the Cube grains in the PAed foils was driven by grain boundary energy. However, the growth for ARed foils was caused by strain induced grain boundary migration (SIBM) driven by the difference in stored energy, between the Cube and the other grains. because the former store less strain energy than the latter after the additional rolling. Furthermore. the grown-up Cube grains having similar orientations met each other and made a cluster in both the foils. Since the Clusters develop to reach the foil surfaces and become stable,, the Cube grains are easy to cover all of the foil in the final stage of annealing.
In present study, abnormally coarsened grains in high purity aluminum foil sheets with cube texture ({100} (001)) after a final annealing was analyzed using SEM/EBSP method. Most of abnormally coarsened grains had Goss({110}〈001〉) or S ({123}〈634〉) orientations. The coarsened grains with Goss and S-orientations were surrounded by Σ5 and Σ7 co-incidence boundaries, respectively. It was found that these coincidence boundaries would enhance the abnormal grain growth of Goss and S oriented grains and that these grains would grow using energy of sub-boundaries between cube-oriented grains as the driving force. The distribution of Goss oriented grains in the partially annealed foil sheets was evaluated by SEM/EBSP method. It was clarified that many Goss-oriented grains were distributed in the transition band on the central layer of the sheets.
In present study, abnormally coarsened grains in high purity aluminum foils with cube texture ({100}< 001 >) after a final annealing was investigated using SEM/EBSP method. Most of abnormally coarsened grains had Goss ({110}< 001 >) or S ({123}< 634 >) orientations. The coarsened grains with Goss and S-orientations were surrounded by Sigma 5and Sigma 7 coincidence boundaries, respectively. This result clarified that these coincidence boundaries would enhance the abnormal grain growth of Goss and S oriented grains. Grain boundary energy of sub-boundaries between cube-oriented grains provided the driving force for the abnormal grain growth. The distribution of Goss oriented grains in the partially annealed foils was characterized by SEM/EBSP method. This characterization revealed that many Goss-oriented grains were distributed in the transition band on the central layer of the sheets.
