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Physical Society Colloquium
Martin Grant
Physics Department The properties of most materials, such as their failure rates under stress, their reactivity, and their magnetic coercivity, depend crucially on the micron-scale microstructure formed during nonequilibrium processing. Pattern formation on these scales is dramatic, and thereby poses a challenge to the fundamental understanding of the formation of complex structure in open systems. We are theoretically studying how elastic fields can affect pattern formation. In particular, we have used a phase-field approach to model the competition between destabilizing elastic effects, and stabilizing effects due to surface energy during epitaxy. We have recovered the stress-driven morphological instability of the surface, including the nonlinear regime in which the surface decomposes into trenches or islands. We have also characterized the coarsening of these surface structures, and are currently studying mechanisms of fracture, as well the formation and propagation of dislocations.
Friday, January 19th 2001, 15:30 |