Effect of sub-micron deformations at opposing strain rates on the micromagnetic behaviour of non-oriented electrical steel

• Published in: Nature communications Vol. 15; no. 1; pp. 9010 - 12
• Main Authors: Winter, Kieran, Liao, Zhirong, Abbá, Erik, Robles Linares, Jose A., Axinte, Dragos
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.10.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 147/137; 147/143; 147/28; 147/3; 639/301/119/997; 639/925/357/997; Deformation effects; Diamond machining; Dislocation; Electrical steels; Humanities and Social Sciences; Magnetic force microscopy; Magnetic materials; Magnetic properties; Manufacturing; Manufacturing industry; Mechanical loading; Mechanical properties; Microscopy; multidisciplinary; Nanoindentation; Performance evaluation; Scanning transmission electron microscopy; Science; Science (multidisciplinary); Steel; Strain; Texture; Time dependence; Transmission electron microscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-53346-7

We are entering an era of re-electrification, seeking high-power density electrical machines with minimal resource use. Significant performance gains in electrical machines have been achieved through precise manufacturing processes, including the shaping/cutting of soft magnetic materials. However, most studies have evaluated magnetic performance at a macro level, focusing on components, while the fundamental mechanisms, e.g., how the micromagnetic behaviour is affected by mechanical interference, remain unclear. In this study, we examine the impact of sub-micron deformations at opposing strain rates (10 −2 to 10 1  s −1 ) on the micromagnetic behaviour of soft magnetic non-oriented electrical steel. Using a diamond probe to indent within a single grain of polycrystalline material at different velocities, we induce quasi-static and dynamic mechanical loading. Our analysis, employing magnetic force microscopy, transmission Kikuchi diffraction, and scanning transmission electron microscopy with a pixelated detector, reveals that magnetic texture disturbances rely on the time-dependent dislocation dynamics of the Fe-BCC material. Additionally, we compress micro-pillars to further investigate these effects under bulk-isolated deformation. These findings highlight the importance of considering even ultra-small loads, such as nano-indentations and micro-pillar compressions, in the manufacturing of next-generation electric machines, as they can affect magnetic texture and performance. Mechanical deformations affect magnetic properties of electrical steels, impacting machine efficiency. Here, authors demonstrate that sub-micron deformations at different strain rates alter micromagnetic behaviour of non-oriented electrical steel due to time-dependent dislocation dynamics.