Morales LÁ, Förner A, Bezold A, Neumeier S, Körner C, Zenk C (2025)
Publication Type: Journal article
Publication year: 2025
Book Volume: 230
Article Number: 115621
DOI: 10.1016/j.matchar.2025.115621
Fe-based BCC superalloys, composed of ∼two thirds Fe and Al by weight, offer a cost effective and sustainable solution for high temperature applications around 700 °C. Introducing Cu into α/α′/α″ superalloys can be used to tune lattice misfit and may contribute to enhance toughness and yield strength. However, understanding how Cu and its interaction with other elements affects the α/α′/α″ microstructure is crucial, as microstructural configuration significantly impacts creep resistance. This study investigates elemental partitioning, segregation, and Cu clustering in an Fe–Al–(Ni,Co)–Ti based α/α′/α″ superalloy containing 1.5 at.% Cu—originally added to improve toughness, inspired by prior ferritic steels. Atom Probe Tomography (APT) and Transmission Electron Microscopy (TEM) reveal that Ni, Al, Co, Ti, and Cu partition into α′/α″ precipitates. Within these, Cu segregates at former Anti Phase Domain Boundaries, where Co and Ti are locally depleted. Due to Cu's limited solubility in Fe and competition for Ni and Al sites, ∼13.7 % and 33.0 % of Cu atoms cluster in the matrix and α′/α″ precipitates, respectively, while ∼86.3% and 67% remain statistically distributed. Cu clusters show asymmetric size distributions: in primary α′/α″ precipitates, the most frequent and median sizes are ∼14.3 nm and 23.7 nm; while in the matrix, where clusters co form with α′ precipitates, the most frequent and median sizes are ∼2.4 nm and 42.0 nm. Additionally, two interfacial dislocation decorations are observed: one enriched with Co and Ti as Cottrell atmospheres and another with a Cu clusters “necklace”. These findings offer critical insights for alloy and heat treatment design strategies aimed at balancing ductility and creep strength through controlled clustering and dislocation interaction.
APA:
Morales, L.Á., Förner, A., Bezold, A., Neumeier, S., Körner, C., & Zenk, C. (2025). Elemental partitioning, defect segregation, and Cu clustering in an Fe-based BCC superalloy. Materials Characterization, 230. https://doi.org/10.1016/j.matchar.2025.115621
MLA:
Morales, Luis Ángel, et al. "Elemental partitioning, defect segregation, and Cu clustering in an Fe-based BCC superalloy." Materials Characterization 230 (2025).
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