کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1449898 | 988717 | 2007 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Atomistic study of athermal cross-slip and its impact on the mechanical properties of iridium
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The mechanical behaviour of the face-centred cubic metal iridium is exceptional in that it undergoes brittle transgranular or intergranular fracture after extensive plastic deformation. We present a model for the origin of this behaviour that is based on the features of the cores of screw dislocations specific to this transition metal. Atomistic simulations performed using a bond-order potential find a planar core structure that corresponds to dissociation into Shockley partials and a metastable, non-planar core spread into two {1Â 1Â 1} planes. Stress-induced transformations between the two core configurations were studied and form the basis for a mechanism for cross-slip that requires neither thermal activation nor full constriction of the partials. The associated high rate of cross-slip leads to extremely intense forest hardening and a dislocation density that increases precipitously with plastic strain to the extent that brittle cleavage is a natural consequence.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 55, Issue 1, January 2007, Pages 161-169
Journal: Acta Materialia - Volume 55, Issue 1, January 2007, Pages 161-169
نویسندگان
M.J. Cawkwell, C. Woodward, D. Nguyen-Manh, D.G. Pettifor, V. Vitek,