7. Diffusion in moving joints – Diffusion-induced migration of grain boundaries

Under the conditions of use, the grain boundaries in which diffusion takes place are mobile (recrystallization, grain growth, creep, etc.). Moreover, diffusion itself is likely to cause movement of the joints. The phenomenon is known by its acronym DIGM (Diffusion Induced Grain Boundary Migration). It must have affected many diffusion experiments. The two phenomena, diffusion in moving joints and Diffusion Induced Grain Boundary Migration (DIGM), are different, and the same level of understanding has not been reached for both. We present them succinctly, particularly for the former, with references to works where the reader can find further information.

• Diffusion in moving joints, although complex, can be approached on the basis of the diffusion equations:

  • we add a term