Fig. 4: Lamellar-to-rod transition in a numerical simulation.

Three-dimensional phase-field simulation of a model alloy with symmetric phase diagram and volume fraction η = 0.34. The tilt of the isotherms with respect to the pulling direction is 4°. Zero-gradient boundary conditions are applied to phase and concentration fields at the front and rear (corresponding to the presence of the glass plates in the experiments) and periodic boundary conditions on the sides. Lamella form at the rear side and slowly elongate, while pinchoff of new rods occurs periodically at the lamella terminations. Color online.