Preferential Composition during Nucleation and Growth in Multi-Principal Elements Alloys

Abstract

The crystallization of complex, concentrated alloys can result in atomic-level short-range order, composition gradients, and phase separation. These features govern the properties of the resulting alloy. While nucleation and growth in single-element metals are well understood, several open questions remain regarding the crystallization of multi-principal component alloys. We use MD to model the crystallization of a five-element, equiatomic alloy modeled after CoCrCuFeNi upon cooling from the melt. Stochastic, homogeneous nucleation results in nuclei with a biased composition distribution, rich in Fe and Co. This deviation from the random sampling of the overall composition is driven by the internal energy and affects nuclei of a wide range of sizes, from tens of atoms all the way to super-critical sizes. This results in short range order and compositional gradients at nanometer scales.

References in corpus (4)

• Robust Structural Identification via Polyhedral Template Matching
• Bond orientational ordering in liquids: Towards a unified description of water-like anomalies, liquid-liquid transition, glass transition, and crystallization
• Impact of lattice relaxations on phase transitions in a high-entropy alloy studied by machine-learning potentials
• Prediction of A2 to B2 Phase Transition in the High Entropy Alloy MoNbTaW