Fundamentals of Thermal Stability of Granular Nanosystems
|Lazar S. Shvindlerman 1,2, Günter Gottstein 2|
1. Russian Academy of Sciences, Institute of Solid State Physics, Chernogolovka 142432, Russian Federation
The main goal of the presentation is to treat the fundamentals of thermal stability of grain microstructure in nanosystems. The consideration is based principally on the experimental, theoretical and computer simulation research which are carried out at the Institute of Physical Metallurgy and Metal Physics, RWTH Aachen University and the Institute of Solid State Physics, Russian Academy of Sciences (Chernogolovka). The contribution of different mobile structural elements and defects of nanocrystalline materials - foreign atoms, vacancies, grain boundary junctions (triple junctions and quadruple points), immobile and mobile particles - to grain growth dragging is quantitatively examined. The results of the first direct measurements of grain boundary excess free volume and the influence of of this grain boundary parameter on the stability of nanocrystals are presented and discussed..It is shownt that grain growth controlled by grain boundary junctions (triple junjctions and quadruple points) kinetics can be used to stabilize a microstructure which will be stable during subsequent annealing at grain boundary kinetics. The derived hierarchy of drag efficiency constitutes an effective engineering tool to assess and compare the role of chemistry and crystals defects on the microsrtuctural stability of nanocrystalline and ultrafine grained materials.
Presentation: Invited at E-MRS Fall Meeting 2007, Acta Materialia Gold Medal Workshop, by Lazar S. Shvindlerman
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-06-25 12:15 Revised: 2009-06-07 00:44