کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1637141 | 1516962 | 2014 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Microstructure evolution and dislocation configurations in nanostructured Al-Mg alloys processed by high pressure torsion
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Microstructure evolution and dislocation configurations in nanostructured Al-Mg alloys processed by high pressure torsion (HPT) were analyzed by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The results show that the grains less than 100 nm have sharp grain boundaries (GBs) and are completely free of dislocations. In contrast, a high density of dislocation as high as 1017 mâ2 exists within the grains larger than 200 nm and these larger grains are usually separated into subgrains and dislocation cells. The dislocations are 60° full dislocations with Burgers vectors of ½<110> and most of them appear as dipoles and loops. The microtwins and stacking faults (SFs) formed by the Shockley partials from the dissociation of both the 60° mixed dislocation and 0° screw dislocation in ultrafine grains were simultaneously observed by HRTEM in the HPT Al-Mg alloys. These results suggest that partial dislocation emissions, as well as the activation of partial dislocations could also become a deformation mechanism in ultrafine-grained aluminum during severe plastic deformation. The grain refinement mechanism associated with the very high local dislocation density, the dislocation cells and the non-equilibrium GBs, as well as the SFs and microtwins in the HPT Al-Mg alloys were proposed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Transactions of Nonferrous Metals Society of China - Volume 24, Issue 12, December 2014, Pages 3848-3857
Journal: Transactions of Nonferrous Metals Society of China - Volume 24, Issue 12, December 2014, Pages 3848-3857
نویسندگان
Man-ping LIU, Ting-hui JIANG, Xue-feng XIE, Qiang LIU, Xue-feng LI, Hans J. ROVEN,