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Session Q02 - Mechanisms for Pattern Formation.
Invited session, Friday morning, March 24, 8:00
Ballroom A2, San Jose Convention Center
During directional solidification of a binary alloy, an array of dendrites may form at the liquid-solid interface. This pattern-forming process may be broken down into three stages: acceleration of an initially flat interface and the concomitant buildup of a solutal boundary layer in front of it; onset of a morphological instability, triggered by thermal fluctuations, producing a relatively finely spaced array of dendritic tips; coarsening of this array and final selection of a steady-state primary spacing. We discuss the theory of Warren and Langer 2702 (1992), as well as supporting theoretical work by Caroli et al. Initial Front Transients in Directional Solidification of Dilute Alloys, J. Crystal Growth, 132, 377 (1993), Karma (1993), and the experiments of Trivedi This work has been confirmed in experiments by Cummins.