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Long-time dynamics of the directional solidification of rodlike eutectics.

Research paper by Mikaël M Perrut, Silvère S Akamatsu, Sabine S Bottin-Rousseau, Gabriel G Faivre

Indexed on: 28 Apr '09Published on: 28 Apr '09Published in: Physical review. E, Statistical, nonlinear, and soft matter physics



Abstract

We report long-duration real-time observations of the dynamics of hexagonal (rodlike) directional-solidification patterns in bulk samples of a transparent eutectic alloy. A slight forward curvature of the isotherms induces a slow dilatation of the growth pattern at constant solidification rate and triggers the rod-splitting instability. At long times, the rod-splitting frequency exactly balances the dilatation driven by the curved isotherms. The growth pattern is then disordered and nonstationary but has a sharply selected mean spacing. Well-ordered growth patterns can be grown using time-dependent solidification rates.