Surface/interface effects on elastic behavior of a screw dislocation in an eccentric core-shell nanowire

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:49

Article

Ahmadzadeh-Bakhshayesh, H.¹  Gutkin, M. Yu.^2,3,4  Shodja, H. M.^1,5 

[1] Sharif Univ Technol, Dept Civil Engn, Tehran 111559313, Iran

[2] Russian Acad Sci, Inst Problems Mech Engn, St Petersburg 199178, Russia

[3] St Petersburg State Polytech Univ, Dept Phys Mat Strength & Plast, St Petersburg 195251, Russia

[4] St Petersburg State Univ, Dept Theory Elast, St Petersburg 198504, Russia

[5] Sharif Univ Technol, Inst Nanosci & Nanotechnol, Tehran 111559161, Iran

关键词: Core-shell nanowire;    Screw dislocation;    Surface stress;    Interface stress;    Image force;   

DOI  :  10.1016/j.ijsolstr.2012.03.020

来源: Elsevier

【 摘 要 】

The elastic behavior of a screw dislocation which is positioned inside the shell domain of an eccentric core-shell nanowire is addressed with taking into account the surface/interface stress effect. The complex potential function method in combination with the conformal mapping function is applied to solve the governing non-classical equations. The dislocation stress field and the image force acting on the dislocation are studied in detail and compared with those obtained within the classical theory of elasticity. It is shown that near the free outer surface and the inner core-shell interface, the non-classical solution for the stress field considerably differs from the classical one, while this difference practically vanishes in the bulk regions of the nanowire. It is also demonstrated that the surface with positive (negative) shear modulus applies an extra non-classical repelling (attracting) image force to the dislocation, which can change the nature of the equilibrium positions depending on the system parameters. At the same time, the non-classical solution fails when the dislocation approaches very close to the surface/interface with negative shear modulus. The effects of the core-shell eccentricity and nanowire diameter on dislocation behavior are discussed. It is shown that the non-classical surface/interface effect has a short-range character and becomes more pronounced when the nanowire diameter is smaller than 20 nm. (C) 2012 Elsevier Ltd. All rights reserved.

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