کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10646569 1001561 2018 23 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Flow strength limit of nanocrystalline tantalum predicted with molecular dynamics simulations
ترجمه فارسی عنوان
محدودیت جریان جریان تانتالیم نانوکریستالین با شبیه سازی دینامیکی مولکولی پیش بینی شده است
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد دانش مواد (عمومی)
چکیده انگلیسی
The effects of grain size (d) on the flow strength (σflow) as well as the deformation mechanism of nanocrystalline tantalum (NC-Ta) under uniaxial tension were investigated with molecular dynamics (MD) simulations. It showed that there exists a critical grain size of dcr = 7 nm, at which σflow reaches the maximum. Generalized stacking fault energy curves suggest that <111>{110} and <111>{112} are the easiest slip systems for dislocations and twins to occur, and after that the other slip systems might be activated. The twinning mechanism of Ta crystal is analyzed to understand the plastic deformation. For the sample with d > 7 nm, the variation of σflow against d follows the Hall-Petch relationship, attributed to the strengthening due to the accumulations of dislocations and twins with the decrease of d. For the sample with d < 7 nm, the variation of σflow against d exhibits an inverse Hall-Petch relationship, attributed to the softening induced by grain boundary activities. Additionally, cracks can be found in the samples with larger d, but they do not significantly propagate and affect the flow stress. Our simulation results could be beneficial to the design and optimization of such kind of high-performance nano-structured materials.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Science and Engineering: A - Volume 738, 19 December 2018, Pages 1-9
نویسندگان
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