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Title: Microstructure of multistage annealed nanocrystalline SmCo 2Fe 2B alloy with enhanced magnetic properties

The microstructure and chemistry of SmCo 2Fe 2B melt-spun alloy after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and 3D atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization. The presence of Sm(Co,Fe) 4B (1:4:1) and Sm 2(Co,Fe) 17B x (2:17:x) magnetic phases were confirmed using both techniques. Fe 2B at a scale of -5 nm was found by HRTEM precipitating within the 1:4:1 phase after the second-stage annealing. Ordering within the 2:17:x phase was directly identified both by the presence of antiphase boundaries observed by TEM and the interconnected isocomposition surface network found in 3D atom probe results in addition to radial distribution function analysis. The variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.
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Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics, 15(6):Article No. 063902
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
SmCo, Magnet; Environmental Molecular Sciences Laboratory