Laser Powder Bed Fusion of anisotropic Nd-Fe-B bonded magnets utilizing an in situ mechanical alignment approach

• Published in: arXiv.org
• Main Authors: Schäfer, Kilian, Rafael Gitti Tortoretto Fim, Maccari, Fernando, Braun, Tobias, Riegg, Stefan, Skokov, Konstantin, Koch, David, Bruder, Enrico, Radulov, Iliya, Ahrens, Carlos Henrique, Paulo Antônio Pereira Wendhausen, Gutfleisch, Oliver
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 05.05.2023
• Subjects: Alignment; Bonding; Chemical bonds; Ferrous alloys; Injection molding; Magnetic fields; Magnetic materials; Neodymium; Net shape; Permanent magnets; Physics - Applied Physics; Physics - Materials Science; Polyamide resins; Powder beds; Remanence
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2305.02867

Nd-Fe-B bonded magnets are an important class of permanent magnets, employed in many technological sectors. The Additive Manufacturing (AM) processes enables the fabrication of net-shape bonded magnets with complex geometries, allowing to tailor their magnetic stray field specifically for a given application. A crucial challenge to be addressed concerning AM of bonded magnets is the production of magnetically anisotropic components. The common approaches presented in the literature up to now, required a post-printing procedure or the complex integration of a magnetic field source into the AM process. Here, we present a technique to fabricate anisotropic bonded magnets via Laser Powder Bed Fusion (LPBF) by utilizing the mechanical alignment of anisotropic particles in a single step, without the need for a magnetic field source. Anisotropic bonded magnets were fabricated using a mixture of anisotropic Nd-Fe-B powder (MQA-38-14) and polyamide-12 (PA12). This magnetic powder consists of ellipsoidal particles, where the easy magnetization axis is distributed perpendicular to their longest side, which can be exploited to generate magnetic texture. Depending on the particle size used as feedstock, the degree of alignment (<cos\((\theta)\)>) can be tailored to a maximum of <cos\((\theta)\)> = 0.78. The fabricated anisotropic bonded magnets exhibited a maximum remanence of Jr = 377 mT and an energy product of (BH)max = 28.6 kJ/m3, respectively.