Dislocation Arrangements Resulting from the Diffusion of Zn into Cu: Electron Microscopy

Zinc from the vapor of 9.75-at. % zinc chips was diffused for 100 h at 780°C into (111) surfaces of thick copper crystals. The density and arrangement of the resulting dislocations were observed on (111) sections by etch pitting and in (111) thin films by transmission electron microscopy. 80% of the dislocations observed by transmission have Burgers vectors in the isoconcentration plane; 70% are organized in low-angle boundaries which have appreciable tilt character. The subgrain size in the isoconcentration plane is about equal to the distance of that plane from the surface. The dislocation density, the subgrain size, and the character of the subgrain boundaries are compared with those predicted for low-energy dislocation arrays accommodating the lattice parameter gradient.