Invited Lecture
Grain boundary diffusion: recent advances

Recent advances on grain boundary diffusion and segregation in bi-crystalline, tri-crystalline, and poly-crystalline metals and alloys are presented with an emphasis on solute diffusion (Ag, Bi, Ge, Ni, Co, Fe) in the same high-purity Cu. The temperature-induced transitions of the grain boundary structure are manifested by the radiotracer diffusion measurements for specific low sigma interfaces [1, 2]. The segregation of Ag at Cu Σ5 and Σ17 grain boundaries is found to be significantly stronger as compared to that at general high-angle grain boundaries as they are present in annealed polycrystalline copper. An existence of critic temperatures, which corresponds simultaneously to specific "kinks" in the temperature dependences of the grain boundary diffusivity and the disappearance of the grain boundary diffusion anisotropy, is discovered and they are related to temperature-induced phase transitions [3].

The state-of-the-art in grain boundary diffusion in intermetallic compounds is reviewed, too, including ordered aluminides and disordered (FCC solid solution) high-entropy alloys.

[1] H. Edelhoff, S. I. Prokofjev, S.V. Divinski, Scr. Mater. 64, 374-377 (2011)

[2] S.V. Divinski, H. Edelhoff, S. Prokofjev, Phys. Rev. B 85 (2012) 144104

[3] T. Frolov, S.V. Divinski, M. Asta, Y. Mishin, Phys Rev Lett 110 (2013) 255502.