کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1562196 999581 2011 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
An analysis on nanovoid growth in body-centered cubic single crystalline vanadium
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مکانیک محاسباتی
پیش نمایش صفحه اول مقاله
An analysis on nanovoid growth in body-centered cubic single crystalline vanadium
چکیده انگلیسی

Molecular dynamics simulations were performed to analyze nanovoid growth in single crystalline vanadium under tension. Radial distribution function at the first nearest neighbor distance was calculated to find out the critical strain rate below which the deformation of specimen was static. Then a tensile stress was exerted on both void contained box and intact box under two constraint conditions. Homogenous dislocations were nucleated in intact box at yield point; while for void contained box with void radius twice the lattice constant, 〈1 1 1〉{1 1 0} shear loops were punched out from void surface. The formation of shear loops was the result of the splitting of purely screw cores on three non-planar planes, as well as their transformations to more stable two-fold non-planar dislocations under tension. The asymmetry of loops was influenced by both strain rate and triaxiality of system. It is also found that, in lower rate cases the yield point and peak stress point coincided; however, the two points separated at higher rate due to the inadequate void growth rate. Mean square displacement of void surface atoms were given out to geometrically depict the void evolution. Moreover, simulations with different initial porosity and box size were performed respectively. It is shown that when void reduced to contain only one vacancy, dislocations can be nucleated independently of the void; when porosity was large enough, the interactions between void and its periodic images were noticeable. Also, when both the void and box were large, triangular prismatic loops on {1 1 0} planes were observed at void surface, which may be contributed to a combined effect of the intersection of shear loops and the ledges along the void surface. Finally, the results of our MD simulations agreed well with that from Lubarda equation.


► The evolution of single nanovoid in single crystalline vanadium was analyzed.
► The effects of strain rate, porosity and specimen size were studied.
► The asymmetry of loops was influenced by both strain rate and triaxiality of system.
► The mean square displacement of surface atom can geometrically depict void evolution.
► Both shear and prismatic loops were emitted at surface of large void.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Computational Materials Science - Volume 50, Issue 8, June 2011, Pages 2411–2421
نویسندگان
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