کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5455575 | 1514639 | 2017 | 24 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Microstructure development of ultra fine grained Mg-22Â wt%Gd alloy prepared by high pressure torsion
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
دانش مواد (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
A hardenable lightweight Mg-22Â wt%Gd alloy with ultra fine grained (UFG) structure was prepared by high pressure torsion (HPT) at ambient temperature. The development of microstructure during HPT processing was investigated. A homogeneous UFG structure with grain size of 300Â nm was achieved after 15 HPT revolutions. The UFG alloy exhibits enhanced strength due to work strengthening by tangled dislocations forming a dense forest throughout grains. Dislocation density in the sample was determined by positron annihilation spectroscopy (PAS) and X-ray line profile analysis (XLPA). It was found that there is an additional source of X-ray profile broadening in addition to small crystallites and micro-strains caused by dislocations. The additional micro-strain component was attributed to lattice modulation by Gd-rich nano-wires formed by agglomeration of Gd solutes and to strains arising from boundaries of crystallite domains and inter-domain interactions. Analysis of the influence of the crystallite size on the strength of UFG Mg-22Â wt%Gd alloy revealed a breakdown in the Hall-Petch relationship when the crystallite size decreased below a critical value of â30Â nm.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Science and Engineering: A - Volume 704, 17 September 2017, Pages 181-191
Journal: Materials Science and Engineering: A - Volume 704, 17 September 2017, Pages 181-191
نویسندگان
J. ÄÞek, P. HruÅ¡ka, T. Vlasák, M. VlÄek, M. JaneÄek, P. Minárik, T. KrajÅák, M. Å lapáková, M. Dopita, R. Kužel, T. KmjeÄ, J.G. Kim, H.-S. Kim,