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.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/12224 must be provided.

1. Motion of Connected Grain Boundaries and Stability of Nanocrystalline Systems
2. Pressure Effect on Grain Boundary Diffusion in Al Bicrystals