It was recalled that, when a polycrystal was brought into contact with a solute source or sink, grain boundaries and liquid films between grains sometimes migrated; leaving behind them a new solid solution which was enriched in, or depleted of, solute atoms. Experiments were performed in order to show that coherency strains in thin diffusion zones ahead of migrating interfaces were the driving force for migration.

D.Y.Yoon: Materials Science Forum, 1996, 204-206, 193-206