TriBeam tomography and microstructure evolution in additively manufactured Alnico magnets

Paul F. Rottmann, Andrew T. Polonsky, Toby Francis, Megan G. Emigh, Michael Krispin, Gotthard Rieger, McLean P. Echlin, Carlos G. Levi, Tresa M. Pollock

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The Alnico 8 alloy has been printed using the selective laser melting additive manufacturing approach, resulting in material with magnetic properties in the as-printed state comparable to properties produced by conventional casting or powder metallurgy routes. Microstructural characterization in 3D, via electron backscattered diffraction (EBSD) in a TriBeam microscope, simultaneously reveals a fine-scale grain structure, grain orientations and sub-grain misorientation gradients as a function of proximity to spherical pores that form during the print process. The nanostructure of the 3D printed part has the same highly coherent spinodal α1//α2 structure observed in conventionally fabricated Alnico 8, which gives rise to a coercivity (Hc) of 51.2 kA m-1. Further investigation of the phase constituents by TEM analysis provides an understanding of the microstructure evolution during the additive manufacturing process. Modified processing pathways for improved microstructure and properties are discussed.

Original languageEnglish
Pages (from-to)23-34
Number of pages12
JournalMaterials Today
StatePublished - Oct 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Ltd


  • Additive manufacturing
  • Alnico
  • Selective laser melting
  • TEM
  • TriBeam

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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