Three-dimensional phase-field simulations are employed to investigate rod-type eutectic growth morphologies in confined geometry. Distinct steady-state solutions are found to depend on this confinement effect with the rod array basis vectors and their included angle ($\alpha$) changing to accommodate the geometrical constraint. Specific morphologies are observed, including rods of circular cross sections, rods of distorted (elliptical) cross sections, rods of peanut-shaped cross-sections, and lamellar structures. The results show that, for a fixed value of $\alpha >{10}^{\circ }$, the usual (triangular) arrays of circular rods are stable in a broad range of spacings, with a transition to the peanut-shaped cross sectioned rods occurring at large spacings (above 1.5 times the minimum undercooling spacing ${\lambda }_{\mathrm{m}}$), and the advent of rod eliminations at low spacings. Furthermore, a transition from rod to lamellar structures is observed for $\alpha <{10}^{\circ }$ for the phase fraction of 10.5% used in the present paper.

• Received 30 March 2011

DOI:https://doi.org/10.1103/PhysRevE.84.011614