Tuesday, May 23

Anisotropic Crystal Growth

1:30 PM-2:15 PM
Room: Liberty B&C
Chair: Peter W. Voorhees, Northwestern University, USA

When a small nucleus of an isotropic solid is placed in a bath of its undercooled melt, it grows if it is large enough, as a sphere until it becomes unstable. If the material anisotrophy is 'small', the sphere will be distorted. If it is 'large', the growing surface will have corners or cusps.

This talk will concern the growth of a hypercooled material with large anisotropy in surface energy. A disturbed planar front will become cellular with corners, edges, or cusps. The speaker will use an asymptotic method to derive a pde evolution equation that predicts interfaces that have bands, square pyramids, etc., depending on the angle between the growth direction and the crystallographic orientation. Long time computations of this equation on a periodic domain yields coarsening rates that are anomalous in time, viz. powers of T that are 1/2 and 1, rather than 1/3.

Stephen H. Davis
Department of Engineering Sciences and Applied Mathematics
Northwestern University, USA
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