Concept of post-eutectic composition for undercooled alloys

TL;DR

This paper introduces the concept of post-eutectic composition in undercooled alloys, linking thermodynamic principles with growth dynamics to identify the most probable alloy composition during solidification.

Contribution

It proposes a new thermodynamic concept and geometric rule for predicting the composition of undercooled alloys in steady state growth conditions.

Findings

Post-eutectic composition minimizes Gibbs free energy release rate.

Parallel tangents rule generalizes the common tangent rule.

Aligns with Prigogine's principle of minimum entropy production.

Abstract

The concept of post-eutectic composition at a fixed undercooling is introduced as the most probable composition in zones of coupled growth. This composition corresponds to the minimum Gibbs free energy release rate in the steady state regime, aligning with Prigogine principle of minimum entropy production for steady states. Geometrically, this is represented by the parallel tangents rule, a generalization of the common tangent rule for transitioning from equilibrium to steady state conditions.