Soft magnetic ternary iron-boron-based bulk metallic glasses

Abstract

Ternary iron-boron-based bulk metallic glasses ͑BMGs͒ were explored exhibiting capability of thick amorphous casting at least 1 mm in rod diameter or 0.5 mm in plate thickness, excellent soft magnetic properties with saturation magnetization 1.56 T and coercivity smaller than 40 A / m, and electrical resistivity larger than 200 ⍀ cm. The BMG alloys represented by the formulas M a Fe b B c are based on two simple selection rules: ͑1͒ M is an element with an atomic radius at least 130% that of Fe; ͑2͒ M possesses eutectic points with both Fe and B, and the M-Fe eutectic is at the Fe-rich end. Among more than 30 candidate M elements, Sc, Y, Dy, Ho, and Er fulfill BMG capability at the composition range, in at %, 3 Ͻ a Ͻ 10, 18Ͻ c Ͻ 27, whereas a + b + c = 100. It is very remarkable that with a tiny addition of M, such as 4 at %, the critical cooling rate to form an amorphous state is abruptly lowered by more than four orders of magnitude as compared with Fe-B binary alloys, and a bulk amorphous state is achievable with only three elements ͑conventional ones 4-7 elements͒. These alloys are promising as core materials for transformers.

Ductile Fe-Based Bulk Metallic Glass with Good Soft-Magnetic Properties

“…On the other hand, it has been suggested 19,20) that BMGs with low T g values are more likely to exhibit ductility. Compared with other iron-based BMGs, [1][2][3][4][5][8][9][10][11][12][13][14][15][16] the ductile Fe 75 Mo 5 -P 10 C 7:5 B 2:5 glassy alloy exhibited lower T g of 708 K, conformity with the correlation between ductility and T g to other ductile BMGs. and high DC permeability () of 47000.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Syntheses of iron-based metallic glasses with high glass-forming ability into a bulk form have further extended their potential applications as structural and functional materials. The first Fe-based bulk metallic glass (BMG) was reported in Fe-Al-Ga-P-C-B system in 1995, 3) subsequently a number of Fe-based BMGs have been developed, such as Fe-Ga-P-C-B-Si and Fe-B-based BMGs with good soft-magnetic properties, [4][5][6][7][8] Fe-Cr-Mo-C-B BMGs with high corrosion resistance, 9) amorphous steel alloys with high GFA and high strength of 3000-4000 MPa, [10][11][12] and Fe-Co-Nb-Si-B BMGs with extremely high strength of over 4000 MPa. 13) A ternary boron-rich Fe-Nb-B BMG with strength near 4 GPa was also recently reported.…”

The observation of surface-softening in Fe-based metallic glass

“…Among the different classes of BMGs, the Fe-based materials are particularly interesting because they exhibit high strength and excellent soft magnetic properties along with very high saturation magnetization [1,[6][7][8][9][10]. The lack of ductility hinders them from different structural applications.…”

“…The study of mechanical properties of bulk metallic glasses (BMGs) is an intriguing field of research from fundamental as well as application point of view [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. One of the major areas of active pursuit being carried out is how to improve the ductility of these materials, an essential factor for structural applications [2][3][4][5]7].…”

Enhancement of glass-forming ability of Fe-based bulk metallic glasses with high saturation magnetic flux density

“…2 In 1995, Inoue and his co-workers first synthesized Fe-based bulk metallic glass (BMG) in the Fe−(Al,Ga)−(P,C,B) system. 3 Since then, a great number of ferromagnetic BMGs have been developed, [4][5][6][7][8][9][10][11] which is encouraging for enlarging the application fields of amorphous soft magnetic materials. Nevertheless, it is not easy to achieve a good combination of the desired GFA and saturation magnetic flux density (B s ) in one glassy alloy, because the addition of glass-forming elements decreases the Fe content, resulting in a decrease in B s .…”