Roadmap towards optimal magnetic properties in L10-MnAl permanent magnets

Our joint work between Technische Universität Darmstadt, the Beihang University and the School of Materials Science and Engineering, Shanghai Jiao Tong University from China on Roadmap towards optimal magnetic properties in L10-MnAl permanent magnets is published in Acta Materialia.

Herein, we propose a strategy to suppress twins’ formation by decreasing the grain and/or particle sizes below a critical size of Dt 300 nm in L10-MnAl permanent magnets, thereby relieving twinning-inducing stress by shifting the balance between volume and surface energy. Generalizing our research findings, we propose a roadmap for selecting the best route for manufacturing high-performance MnAl magnets, depending on their grain/particle size. The dependence of coercivity on grain/particle sizes shows that optimal coercivity can be reached within the range of 50–200 nm, which also shows a pathway to achieve the twin-free microstructure allowing the achievement of high texture degree in polymer-bonded or sintered magnets textured in a magnetic field. The results reported here can be applied to other twin-containing permanent magnet compounds, offering opportunities to drastically increase their texture and maximal energy products.

Y. Jia, Y. Wu, Y. Xu, R. Zheng, S. Zhao, K. P. Skokov, F. Maccari, A. Aubert, O. Gutfleisch, J. Wang, H. Wang, J. Zou, C. Jiang
Acta Materialia, 245, 118654 (2023).
DOI: 10.1016/j.actamat.2022.118654