Berlin 2005 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DS: Dünne Schichten

DS 7: Ionenstrahlverfahren I

DS 7.1: Hauptvortrag

Samstag, 5. März 2005, 13:45–14:30, TU HS107

The role of ion irradiation induced viscous flow in thin film structuring: Hard matter going soft — •S.G. Mayr — I. Physikalisches Institut, Georg–August–Universität Göttingen, Friedrich–Hund–Platz 1, 37077 Göttingen

Ion beams provide unique opportunities for modifying thin film structural and mechanical properties on length scales ranging from several nanometers to macroscopic dimensions. In a variety of materials, including polycrystalline and amorphous metals and semiconductors, plastic effects can dominate, which originates from processes in the small volumes of materials affected by a single ion impact. The underlying atomic–scale kinetics as well as its applications for self–organized structuring are investigated using a combination of experiments and molecular–dynamics (MD) computer simulations: We report experiments, that illustrate the impact of radiation induced viscous flow on morphology and stresses, such as interface smoothing [1], stress relaxation, radiation induced sintering or self–organized pattern formation. Using MD simulations [2] we study the underlying atomic–scale mechanisms for the two energy regimes, where local melting along the ion track is either dominant or not. We show, that macroscopic plastic flow does not require melting, indicating, that defect–like entities are sufficient to mediate plastic flow.
Financially supported by the DFG–SFB 602, TP B3

[1] S.G. Mayr and R.S. Averback, Phys. Rev. Lett. 87 (2001), 196106

[2] S.G. Mayr, Y. Ashkenazy, K. Albe and R.S. Averback, Phys. Rev. Lett. 90 (2003), 55505