Dresden 2003 – wissenschaftliches Programm

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M: Metallphysik

M 4: Hauptvortrag Winning

M 4.1: Hauptvortrag

Montag, 24. März 2003, 14:00–14:30, IFW A

Grain Boundary Mechanics - Novel Tool for Microstructure Control — •Myrjam Winning — Institut fuer Metallkunde und Metallphysik, RWTH Aachen, Kopernikusstr. 14, 52056 Aachen

The motion of grain boundaries is the key phenomenon of recrystallization and grain growth and dominates the evolution of texture and microstructure, i.e the macroscopic physical and mechanical properties of a material, in particular of a part in service. The reaction of grain boundaries to mechanical stresses is reviewed. It was found that the motion of low angle grain boundaries as well as of high angle grain boundaries can be induced by the imposed external stress. The observed activation enthalpies allow conclusions on the migration mechanism of the grain boundary motion. The motion of planar low and high angle grain boundaries under the influence of a mechanical stress field can be attributed to the movement of the grain boundary dislocations which comprise the structure of the boundary. A sharp transition between low and high angle grain boundaries was observed for different tilt axes. Also an influence of the mechanical stress on grain growth was investigated. The fact that boundaries can also be moved by mechanical forces sheds new light on microstructure evolution during elevated temperature deformation.