Dislocation dipoles in a square hollow prismatic nanowire embedded in an infinite-size matrix

Abstract

The introduction of dipoles of edge dislocations symmetrically displayed with respect to the center of a composite structure made of a square hollow prismatic nanowire embedded in an infinite-size matrix has been theoretical investigated when misfit strain is present in both phases. When the dipole is composed of dislocations of Burgers vectors such that the misfit strain cannot be screened by the dislocations lying into the interfaces, the gliding and climbing components of the Peach–Koehler force applied on the dislocations have been calculated and the unstable equilibrium positions of the dipole have been determined versus the misfit strain and nanowire geometric parameters. When the Burgers vectors are such that the misfit strain can be released when the dislocations have reached the interfaces, the formation of the dipole from the matrix center to the inner matrix-nanowire interfaces has been analyzed from an energy variation calculation. A critical size of the nanowire for which the dislocation formation in the inner interfaces is favorable at a stable position has been finally determined versus the misfit parameter.