Defects and multistability in eutectic solidification patterns

TL;DR

This paper uses 3D phase-field simulations to explore complex defect-rich patterns in eutectic solidification, revealing a continuum of structures and hysteresis effects that align with experimental observations.

Contribution

It uncovers a wide variety of stable defect-laden patterns and demonstrates a gradual lamellae-to-rod transition with hysteresis, expanding understanding of eutectic pattern formation.

Findings

Existence of numerous defect-stabilized patterns

Disordered patterns blur lamellar and rod distinctions

Transition between patterns exhibits hysteresis

Abstract

We use three-dimensional phase-field simulations to investigate the dynamics of the two-phase composite patterns formed upon during solidification of eutectic alloys. Besides the spatially periodic lamellar and rod patterns that have been widely studied, we find that there is a large number of additional steady-state patterns which exhibit stable defects. The defect density can be so high that the pattern is completely disordered, and that the distinction between lamellar and rod patterns is blurred. As a consequence, the transition from lamellae to rods is not sharp, but extends over a finite range of compositions and exhibits strong hysteresis. Our findings are in good agreement with experiments.