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||Materials and Optoelectronic Science|
|Type of Document
||Investigation of annealing texture evolutions in an aluminum-magnesium alloy deformed by different cold-rolling reductions|
|Date of Defense
||electron backscatter diffraction
5052 aluminum-magnesium alloy
||In this study, the hot rolled plates of 5052 aluminum-magnesium alloy were subjected to different cold rolling processes, which are cold rolling reductions of 70% and 90% (referred as CR 70 and CR 90) hereafter. The CR specimens were subsequent annealed at different temperatures. Thus, the effects of different cold rolling reductions and subsequent annealing treatments on the texture and microstructure changes were observed.|
The textures of the surface layer and the central area of the CR and annealed specimens were analyzed by X-ray diffraction (XRD), and then the orientation distribution functions (ODFs) were obtained. The hot rolled plates were analyzed to have a strong intensity of Cube orientation. After rolling, it can be found that Cube orientation dominates in the CR 70 sample and β-fiber is the main texture in the CR 90 specimen. The CR 70 specimens were annealed at different temperatures (280 ℃ to 300 ℃) for one hour. The results show that the strength of textures decreased with increasing annealing temperature, but the Cube orientation intensity remained the highest. The CR 90 specimens were annealed at 270 ℃ and 280 ℃ for one hour. The results show that the intensity of the β-fiber decreased with increasing annealing temperature, but Cube and Goss orientations increased with annealing temperature.
Ex-situ experiments were conducted on the specimens by electron backscatter diffraction (EBSD). The cold rolled specimens were analyzed and the same areas were then re-analyzed after annealing. The results of specimens subjected to different cold rolling reductions and annealing treatments show that the orientations of recrystallization are related to the orientation of the cold-rolled structure. From the experimental results, three ways of developing the Cube orientations can be summarized. (i) The Cube band in the cold-rolled structure can easily grow in the ND direction after annealing, (ii) The fragment Cube orientation between the S and Cu orientations in the cold-rolled structure can easily nucleate and grow after annealing, (iii) Cube orientation disappeared when other textures have faster growth rates than Cube orientation.
||Po-we Kao - chair|
Chung-yi Yu - co-chair
Pei-ling Sun - advisor
Indicate in-campus at 2 year and off-campus access at 99 year.|
|Date of Submission