3D magnetic patterning in additive manufacturing via site-specific in-situ alloy modification. (March 2020)

• Record Type: Journal Article
• Authors: Arabi-Hashemi, Ariyan; Maeder, Xavier; Figi, Renato; Schreiner, Claudia; Griffiths, Seth; Leinenbach, Christian
• Is Part Of: Applied materials today. Volume 18(2020)
• Publication Date: 2020-03
• Subjects: Laser powder bed fusion -- In-situ alloying -- Magnetic patterning -- High nitrogen steel -- Site-specific microstructure; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2019.100512
• Languages: English
• ISSNs: 2352-9407

Abstract

Graphical abstract: Highlights: High nitrogen steel (HNS) powder consolidated by laser powder bed fusion. Site specific control of nitrogen content by varying volumetric energy density. Laser powder bed fusion allows 3d printing unique, complex magnetic structures. In-situ alloying approach is applicable to materials containing volatile elements. Abstract: Controlling the process-microstructure-properties relationship is at the heart of materials science. Thus in-situ compositional control in additive manufacturing has the potential to innovate present materials AM processing. We demonstrate in-situ alloy modification during laser powder bed fusion (LPBF) processing with the site-specific control of the para- and ferromagnetic properties in a high-nitrogen steel part fabricated by LPBF. Nitrogen can be selectively evaporated during the LPBF process by varying the volumetric energy density. The controlled evaporation of nitrogen stabilizes the ferromagnetic bcc phase at the expense of the paramagnetic fcc phase as shown by experiments and thermodynamic simulations. We demonstrate the feasibility to print complex magnetic structures by a 3D magnetic chessboard pattern comprised of non-ferromagnetic and partially ferromagnetic areas. The presented approach is applicable to all alloys where volatile elements affect the microstructure.