Grain rotation in nanocrystalline layers under influence of swift heavy ions

I. Zizak (1) , N. Darowski (2) , S. Klaumunzer (2) , G. Schumacher (2) , J.W. Gerlach (3) , W. Assmann (4)

1 Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung mbH
2 Hahn-Meitner-Institute
3 IOM - Leibniz-Institut für Oberflächenmodifizierung
4 LMU - Ludwig Maximilian University [Munich] = Ludwig Maximilians Universität München

Significant changes in texture occur in nanocrystalline Ti, TiN, and NiO layers during irradiation with 350 MeV Au ions. The angle between ion beam and layer normal was between 30° and 70°. The major effect is a collective rotation of the nanocrystals. In case of omega-Ti layers the texture rorated by more than 70° at an ion fluence of 3e15 Au/cm2. In addition to grain rotation, the layers exhibit a shear motion like that observed previously with amorphous materials. Below about 1e15 Au/cm2 the grain growth is small and grain rotation is reversible, i.e. reversing the irradiation direction and applying the same fluence, the grains roll back into their original orientation. The second observed effect is the alignment of the grains, whose coalescence eventually leads to a mosaic crystal. However, grain rotation is absent or immeasurably small in micro-crystalline titanium. An attempt to understand the processes in nanocrystalline materials in terms of amorphous grain boundaries, as well as the disclination dipole diffusion along the grain boundary was made.

Mots clés: SHIM; Material Modification; Texture; Ion Hammering; Nanocrystalline Materials

Domaines: Science des matériaux [cond-mat.mtrl-sci]

I. Zizak, N. Darowski, S. Klaumunzer, G. Schumacher, J.W. Gerlach, et al.. Grain rotation in nanocrystalline layers under influence of swift heavy ions. The Seventh International Symposium on Swift Heavy Ions in Matter, Jun 2008, Lyon, France. ⟨hal-00256625⟩