Overcoming mechanical fragility in Sm-Co permanent magnet materials

• Published in: Acta materialia Vol. 196; no. C; pp. 528 - 538
• Main Authors: Cui, Baozhi, Liu, Xubo, King, Alexander H., Ouyang, Gaoyuan, Nlebedim, Cajetan I, Cui, Jun
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.09.2020; Elsevier
• Subjects: Heterogeneous microstructures; MATERIALS SCIENCE; Mechanical and magnetic properties; Sm-Co sintered magnets; Heterogeneous microstructures; Sm-Co sintered magnets; Mechanical and magnetic properties
• ISSN: 1359-6454; 1873-2453; 1873-2453
• DOI: 10.1016/j.actamat.2020.06.058

Samarium-cobalt alloys are used in some of the strongest permanent magnets, particularly for applications between about 200 and 550°C, but the utilization of these materials is restricted by their brittleness. Improving their mechanical resilience would allow them to be used more widely and, in some cases, substitute for neodymium-based magnet alloys which are subject to supply-chain risks. We have engineered a series of novel microstructures with bi-modal grain size distributions to achieve unprecedented combinations of mechanical and magnetic properties. Improvements up to 73% are obtained in the flexural strength of Sm2(CoFeCuZr)17 sintered magnets, with negligible impact on the magnetic properties. Our mechanically-robust, high-performance Sm-Co magnets are made without changing the chemical compositions of the materials or their heat treatment procedures, making them highly compatible with existing manufacturing processes. [Display omitted]