Dresden 2006 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MM: Metall- und Materialphysik

MM 7: Symposium Severe Plastic Deformation II

MM 7.5: Fachvortrag

Montag, 27. März 2006, 17:00–17:30, IFW A

Diffusion in nanocrystalline materials — •Wolfgang Sprengel — Institut für Physikalische Elektronik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany; sprengel@ipe.uni-stuttgart.de

Atomic diffusion represents a key issue for nanocrystalline materials since it controls both, their physical properties, such as plasticity, and their structural stability. Diffusion in nanocrystalline solids substantially differs from diffusion in coarse-grained or single-crystalline materials. In nanocrystalline solids the high fraction of crystallite interfaces provides paths of high diffusivity. Due to the correlation between the diffusion behavior and the interface structure, diffusion measurements can serve as an important tool to solve the controversial debate to what extent interface structures in nanostructured materials differ from those of conventional grain boundaries. An overview will be given on atomic diffusion in nanocrystalline materials prepared by various synthesis routes including crystallization, crystallite condensation and compaction, and severe plastic deformation. The role of intergranular amorphous phases and of interfacial structural relaxation will be addressed. Diffusion studies in nanocrystalline alloys which show an intergranular melting transition will be presented [1,2].

[1] M. Eggersmann et al., Interface Science 9, 337 (2001).

[2] W. Sprengel et al., J. Appl. Phys. 98, 074314 (2005).