Grain boundaries dislocation models

Figure C2.11.6. The classic two-particle sintering model illustrating material transport and neck growtli at tire particle contacts resulting in coarsening (left) and densification (right) during sintering. Surface diffusion (a), evaporation-condensation (b), and volume diffusion (c) contribute to coarsening, while volume diffusion (d), grain boundary diffusion (e), solution-precipitation (f), and dislocation motion (g) contribute to densification.

Short-circuit diffusion along grain boundaries has been studied extensively via experiments and modeling. Because diffusion along dislocations and crystal surfaces is comparatively less well characterized, particular attention is paid to grainboundary transport in this chapter. However, briefer discussions of diffusion along dislocations and free surfaces are also presented. 

The example in Fig. 13.4 is an extension of the model for the motion of a small-angle boundary by the glide and climb of interfacial dislocations (Fig. 13.3). Figure 13.4 presents an expanded view of the internal surfaces of the two crystals that face each other across a large-angle grain boundary. Crystal dislocations have... 

W.T. Read and W. Shockley. Dislocations models of grain boundaries. In Imperfections in Nearly Perfect Crystals. John Wiley Sons, New York, 1952. 

---