Molecular Dynamics Simulation of Grain Boundary Migration - Softcover

Zhou, Jian

Softcover

ISBN 10: 3954040425 ISBN 13: 9783954040421

Verlag: Cuvillier Verlag, 2012

Inhaltsangabe

Migration of tilt grain boundaries (GBs) in aluminum has been simulated in a wide temperature range with various magnitudes of driving force. It is found that under different conditions GBs migrate through either a diffusionless or a diffusional mechanism. The essence of the diffusionless mechanism is determined to be GB dislocation glide. This mechanism agrees with many previously reported mechanisms, consisting of the collective motion of atom groups, the four-atom shuffling and the boundary motion by glide of primary/secondary GB dislocations. GB dislocation glide therefore serves as a generalized mechanism for all of them. The diffusional mechanism is merely observed to occur for high-angle GBs at high temperatures when a relatively small driving force of several MPa is applied. For these GBs featured in thick and highly disordered structures, GB migration is controlled by GB diffusion. The effects of structural constraints, temperature, GB misorientation and driving force magnitude, on the activation of either mechanism as well as on concrete GB migration behaviors are discussed. Based on these discussions, two GB migration mechanism maps for polycrystals are proposed. The mechanism maps can well explain many contradictory findings obtained previously in both experiments and simulations. In addition, GB mobilities are evaluated at a high temperature. The simulated values are physically reasonable as high-angle GBs move faster than low-angle GBs and the maximum mobility occurs around 40° misorientation. The mobility of a Σ7 GB even approaches the maximum experimental value obtained in ultra-high-purity bicrystals.

Über diesen Titel

Über die Autorin bzw. den Autor

Personal data Name: Jian Zhou Date and place of birth: 03.1981, Wujiang China Education 1999 - 2003 B.Sc. in Biomedical Engineering, Southeast University, China. 2003 - 2005 M.Sc. in Biomedical Engineering, Southeast University, China. 10/2005 - 11/2007 M.Sc. in Advanced Materials, Ulm University, Germany 03/2008 - 02/2012 A doctoral candidate in the Institute of Physical Metallurgy and Metal Physics, RWTH Aachen University, Germany

Details zur Ausgabe

• Verlag: Cuvillier Verlag
• Erscheinungsdatum: 2012
• Sprache: Englisch
• ISBN 10: 3954040425
• ISBN 13: 9783954040421
• Einband: Taschenbuch
• Auflage: 1
• Anzahl der Seiten: 100
• Kontakt zum Hersteller: preigu GmbH & Co. KG; mail@preigu.de; ; Lengericher Landstr. 19; Osnabrück; Niedersachsen; 49078; Deutschland