Abstract
The mechanical properties, specifically ductility, of high performing soft magnets such as Fe-Co alloys are a limiting factor to their broader use in a number of systems. The understanding of the mechanical robustness in these materials is currently insufficient to be able to support the growing interest in applications such as magnetic shielding or electric motors. Fe-Co alloys provide the highest commercially available magnetic saturation and high magnetic permeability but have very poor ductility. The addition of vanadium to these alloys has allowed for significant commercialization and some ductility improvements, but the fundamental reasons for the observed improvements are not well understood. In most published work on mechanical properties in these alloys, the precise chemistry of the alloys investigated, often a critical aspect of intermetallic, is not reported or controlled and thermal history is unclear. This work creates a ductility model that is sensitive to changes in chemistry and can predict relative strain to failure as well as brittle fracture mode for intermetallic and is applied to Fe-Co alloys. Through the application of density functional theory (DFT), this model identifies defect stabilities, anti-phase boundary (APB) energies, the energy necessary to cross-slip, and cleavage energies and combines them through energetic competition to determine a relative failure strain. The model correctly predicts ductility improvements with the addition of vanadium as well as the transition from intergranular to trans granular cleavage, though more precise experiments are necessary to appropriately validate the various improvements observed.
Recommended Citation
W. Everhart and J. Newkirk, "A General Model for the Ductility of Intermetallics Applied to Fe-Co Alloys," Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, vol. 55, no. 12, pp. 5090 - 5099, Springer; ASM International, Dec 2024.
The definitive version is available at https://doi.org/10.1007/s11661-024-07588-1
Department(s)
Materials Science and Engineering
Publication Status
Full Access / Open Access
International Standard Serial Number (ISSN)
1073-5623
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 Springer; ASM International, All rights reserved.
Publication Date
01 Dec 2024
Comments
U.S. Department of Energy, Grant DE-NA-0002839