Image force and stability of a screw dislocation inside a coated cylindrical inhomogeneity with interface stresses

• Published in: Acta mechanica 2011-08, Vol.220 (1-4), p.315-329
• Main Authors: Feng, H., Fang, Q. H., Liu, Y. W., Jin, B.
• Format: Article
• Language: English
• Subjects: Analysis; Classical and Continuum Physics; Coatings; Composite materials; Condensed matter: structure, mechanical and thermal properties; Control; Cylinders; Defects and impurities in crystals; microstructure; Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.); Dislocations; Dynamical Systems; Engineering; Engineering Thermodynamics; Exact sciences and technology; Heat and Mass Transfer; Image force; Inhomogeneity; Interface stresses; Mathematical models; Mechanical engineering; Mechanical properties; Physics; Screw dislocations; Solid Mechanics; Stability; Stress analysis; Structure of solids and liquids; crystallography; Theoretical and Applied Mechanics; Vibration
• ISSN: 0001-5970; 1619-6937
• DOI: 10.1007/s00707-011-0489-8

The image force and stability of a screw dislocation inside a coated cylindrical inhomogeneity with interface stresses are analyzed. A three-phase composite cylinder model is utilized to study the issues. The stress boundary condition at the interface of the coating layer is modified by incorporating surface/interface stress. The analytical solution of complex functions of the inhomogeneity, the coating layer, and the infinite matrix is derived by means of the complex variable method. With the aid of the obtained stress fields and the Peach–Koehler formula, the explicit expression of the image force acting on the screw dislocation is obtained. The critical radius of the inhomogeneity where the screw dislocation stays is evaluated. The influence of the interface stresses on the image force and the critical radius of the inhomogeneity is derived. The results indicate that the negative interface stresses attract the dislocation, and the positive interface stresses repel the dislocation. The critical radius of inhomogeneity will increase for considering the negative interface stresses and will decrease for considering the positive interface stresses.