Q.H. Fang

Screw Dislocations in a Three-Phase Composite Cylinder Model With Interface Stress

A three-phase composite cylinder model is utilized to study the interaction between screw dislocations and nanoscale inclusions. The stress boundary condition at the interface between nanoscale inclusion and the matrix is modified by incorporating surface/ interface stress. The explicit solution to this problem is derived by means of the complex variable method. The explicit expressions of image forces exerted on screw dislocations are obtained. The mobility and the equilibrium positions of the dislocation near one of the inclusions are discussed. The results show that, compared to the classical solution (without interface stress), more equilibrium positions of the screw dislocation may be available when the dislocation is close to the nanoscale inclusion due to consider interface stress. Also, the mobility of the dislocation in the matrix will become more complex than the classical case.

Misfit dislocation dipoles and critical parameters of buried strained nanoscale inhomogeneity

A theoretical model is suggested which describes the generation of the misfit dislocation dipole in the system of the soft infinite matrix containing a circular stiff nanoscale inhomogeneity. The critical conditions of misfit dislocation dipole formation and the equilibrium position (preferred location) of the misfit dislocation dipole are given. The influence of the ratio of the shear modulus, the misfit stain, and the equilibrium position of the dislocation on the critical radius of the inhomogeneity is investigated.