Size effect of layer thickness on stress fields due to interface core-spreading dislocation arrays in multilayers

Abstract

The elastic fields due to interface dislocation arrays with spreading core in multilayers are derived analytically by means of the superposition of Green function of individual compact dislocations. The numerical results for Cu-Nb multilayers with dislocation arrays demonstrate that: (1) There exists a critical layer thickness (CLT) in describing interface shear stress. The maximum interface shear stress (MISS) increases with the layer thickness as it exceeds CLT; while the MISS decreases rapidly with the layer thickness as it is thinner than CLT. (2) Both the density and core width of interface dislocations have salient effect on the stress fields. The overall stress field is confined by high density of dislocations, and the stress singularity is released by core spreading. (3) A new dislocation prefers to glide in the middle region between the two adjacent interface dislocations by means of Peach-Kohler (P-K) force acting on the dislocation and elastic energy of dislocations. These findings would provide foundations to deepen the understanding of microscopic plastic deformation mechanisms and their related macroscopic mechanical properties of metallic anisotropic multilayers.