1995 Volume 59 Issue 10 Pages 1013-1017
The effects of segregation of alloying elements (P, Bi and Ag) on the boundary-dependent capability of grain-boundary sliding of various [011] symmetric tilt boundaries in Cu have been investigated below 573 K from experiments using an electron microscope technique. The technique utilizes the sliding-induced rotation of moiré fringes on boundary BCC Fe-Co particles in an aged Cu-Fe-Co alloy and is capable of detecting sliding of less than 1 nm. The viscosity of a boundary increases and then reaches a saturation stage as the amount of segregation of each element increases. At the saturation stage, the activation energies Q for sliding are in agreement with those Qv for the bulk diffusion of the elements in Cu. For boundaries which have values of Q larger than Qv before adding the elements, the boundary viscosity is not affected by the segregation of the elements. These experimental results can be explained qualitatively from the viewpoint of grain-boundary diffusion.
