Beyond steady-state lamellar eutectic growth

Lamellar eutectics only grow in steady state over a small range of melt compositions between the two solidus lines of a binary phase diagram. Outside this range their growth exhibits a rich dynamical behavior. A random-walk model is constructed to simulate eutectic solidification of a thin film and applied to study this behavior. In addition to oscillatory modes, a ``tilting instability'' on the lamellar spacing is found at off-eutectic compositions. Well into nonlinear regimes, this instability causes lamellae from the minor phase to follow convoluted solidification paths thereby generating exotic eutectic textures.