Novel CoFeAlMn high-entropy alloys with excellentsoft magnetic properties and high thermal stability

• Published in: Journal of materials science & technology Vol. 153; pp. 22 - 31
• Main Authors: Gao, Wei, Dong, Yaqiang, Jia, Xingjie, Yang, Liping, Li, Xubin, Wu, Shouding, Zhao, Ronglin, Wu, Hang, Li, Qiang, He, Aina, Li, Jiawei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2023
• Subjects: High saturation magnetization; High-entropy alloys; Magnetic domain; Magnetic properties; Soft magnetic powder cores; High saturation magnetization; High-entropy alloys; Soft magnetic powder cores; Magnetic domain; Magnetic properties
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/j.jmst.2023.01.010

•Co4Fe2AlxMny alloys were designed to develop HEAs with good magnetic properties.•Co4Fe2Al1.5Mn1.5 HEA has the highest ms of 161.3 emu g–1 in developed HEAs.•Mn shift from antiferromagnetic to ferromagnetic with the help of Al.•Co4Fe2Al1.5Mn1.5 HEA has a structure of the B2 phase distributed in the DO3 matrix.•Co4Fe2Al1.5Mn1.5 HEA has good temperature stability up to 600 °C. High-entropy alloys (HEAs), which are composed of 3d transition metals such as Fe, Co, and Ni, exhibit an exceptional combination of magnetic and other properties; however, the addition of non-ferromagnetic elements always negatively affects the saturation magnetization strength (Ms). Co4Fe2AlxMny alloys were designed and investigated in this study to develop a novel HEA with excellent soft magnetic properties. The Co4Fe2Al1.5Mn1.5 HEA possesses the highest Ms of 161.3 emu g–1 thus far reported for magnetic HEAs, a low coercivity of 1.9 Oe, a high electrical resistivity of 173 μΩ cm, a superior thermal stability up to 600 °C, which originates from the novel microstructure of B2 nanoparticles distributed in a DO3 matrix phase, and the crucial transition of Mn from antiferromagnetism to ferromagnetism with the assistance of Al. The Co4Fe2Al1.5Mn1.5 HEA was selected to produce micron-sized powder and soft magnetic powder cores (SMPCs) for application in the exploration field. The SMPCs exhibit a high stable effective permeability of 35.9 up to 1 MHz, low core loss of 38.1 mW cm–3 (@100 kHz, 20 mT), and an excellent direct current (DC) bias performance of 87.7% at 100 Oe. This study paves the way for the development of soft magnetic HEAs with promising applications as magnetic functional materials.