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M: Metallphysik

M 49: Grenzfl
ächen I

M 49.2: Vortrag

Dienstag, 8. März 2005, 15:00–15:15, TU H2038

Magnetically driven selective grain growth — •Peter J. Konijnenberg, Dmitri D. Molodov, and Günter Gottstein — Institut für Metallkunde und Metalphysik, RWTH-Aachen, 52074 Aachen

Thanks to an increasing field strength of resistive wide bore high field magnets, non-ferromagnetic anisotropic materials become increasingly interesting for magnetic annealing. In these materials a driving force for grain boundary migration can be induced by an appropriately directed and suitably high external magnetic field. Thermodynamically this stems from a difference in free energy density between adjacent grains.

It is experimentally shown that annealing of locally deformed single crystals (Zn, 99.99+%) in a high magnetic field, directed along the extraordinary axis, results in growth of individual selectively grown macroscopic grains into the single crystalline host matrix. Results are discussed in terms of grain orientation and grain boundaries between these grains and the host matrix in Rodrigues-Frank parameterization. It is shown that the boundary population is clearly non-randomly distributed, independently of the crystallographic deformation direction. Furthermore, in comparison with an identical but only locally at zero field recrystallized sample series, the boundary population after magnetic annealing is clearly biased towards large disorientation angles.

On rolled, recrystallized and magnetically annealed α-Ti (CP) it is shown how a similar growth selection also affects texture evolution in a polycrystalline aggregate.