Solidification Dynamics of Undercooled Alloy Systems

Solidification dynamics in undercooled alloy systems examine how metallic melts, cooled below their equilibrium liquidus temperature without immediate crystallisation, evolve microstructurally as they solidify. In this metastable regime, undercooling increases the thermodynamic driving force for nucleation and accelerates growth kinetics, giving rise to distinctive phenomena such as rapid dendritic growth, anomalous eutectic morphologies and solute trapping. The release of latent heat during recalescence often produces transient thermal spikes that influence grain refinement, phase selection and interfacial stability. Convection—whether thermally driven, magnetically induced or containerless—further modulates transport of heat and solute, leading to variations in grain boundary migration and microsegregation. Theoretical models now couple classical nucleation theory with interface-controlled growth laws, enabling prediction of dendrite tip velocity, undercooling thresholds for eutectic transitions and migration of solidification grain boundaries. Practically, control over undercooling and its associated dynamics underpins advances in additive manufacturing, high-performance casting and the production of high-entropy and medium-entropy alloys. Global applications span aerospace components with tailored microstructures, automotive parts with improved fatigue resistance and energy materials designed for corrosion-resistant service.

Research from Nature Portfolio

Recent studies have elucidated how solidification grain boundaries migrate independently of solute segregation, extending classical grain-boundary theory to undercooled conditions. A theoretical framework, validated across multiple binary alloys, revealed that migration is insensitive to cooling rate yet strongly dependent on solute type and grain size, with implications for intergranular cracking and corrosion resistance. Foundational work on a multinary Fe-Ni-Mo-Ge-Co alloy demonstrated that once undercooling exceeds a critical value, dendritic growth velocity rises sharply before plateauing, with accelerated growth refining grains and enhancing hardness. These findings unite kinetics and thermodynamics to predict microstructural transitions from trunk-like dendrites to equiaxed morphologies as undercooling varies.

Solidification Dynamics of Undercooled Alloy Systems publication trend

The graph below shows the total number of articles in solidification dynamics of undercooled alloy systems across all publications each year (not limited to Nature Index journals).

Technical terms

Undercooling: The process of cooling a liquid below its equilibrium freezing point without immediate crystallisation, increasing the driving force for nucleation.

Recalescence: A transient rise in temperature during solidification as latent heat is released upon phase change.

Dendritic growth: Tree-like crystal growth morphology formed when anisotropic interface kinetics dominate undercooling-driven solidification.

Eutectic structure: A fine, inter-lamellar mixture of two solid phases that solidify simultaneously at a characteristic eutectic composition and temperature.

Solute trapping: The retention of solute atoms in the solid phase at concentrations higher than equilibrium values due to rapid interface advancement.

References

1. Origin identification and regulation of BCC precipitation in a CoCrFeNi high entropy alloy. Materials Research Letters (2024).
2. Microstructural and Mechanical-Property Manipulation through Rapid Dendrite Growth and Undercooling in an Fe-based Multinary Alloy. Scientific Reports (2016).
3. Migration of solidification grain boundaries and prediction. Nature Communications (2022).
4. Magnetic Field-Dependent Microstructure Evolution of Solidified Co39.2Ni39.2Al21.6 Eutectic Medium-Entropy Alloy. Crystals (2023).