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MM: Metall- und Materialphysik

MM 9: Interfaces

MM 9.4: Vortrag

Montag, 27. März 2006, 15:30–15:45, IFW D

Examination of Grain Rotation Kinetics by Orientational Imaging Microscopy (OIM) — •M. Ziehmer¹, A. Tschöpe¹, C. Krill², and R. Birringer¹ — ¹Technische Physik, Universität des Saarlandes, 66041 Saarbrücken — ²Elektrotechnik, Universität Ulm, 89081 Ulm

The specific grain boundary energy γ depends on the misorientation θ of the adjacent grains. As a consequence, a torque which is proportional to the derivative of γ with respect to θ is acting on the grains . Sufficient thermal energy provided, this torque results in a rotation of the grains into local energy minimum configurations.

There are several open questions concerning the functional form of γ with respect to θ and the influence of grain boundary spatial extent on the rotation rate and the rotation mechanisms, which could all be enlightened by examining the rotation kinetics of individual grains.

We report on measurements of grain rotations in terms of the established method of spheres sintered onto a flat substrate. Both substrate and spheres are made of single crystalline copper. We take advantage of the progress in experimental techniques and use OIM for the measurement of the relative orientation of sphere and substrate. This method enables to study the rotations of single spheres over several orders of magnitude in grain boundary extent.