1 School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China 2 Key Lab of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024, China 3 Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022, China
Cite this article:
Yaoxiang GENG,Zhijie ZHANG,Yingmin WANG,Jianbing QIANG,Chuang DONG,Haibin WANG,Ojied TEGUS. Structure-Property Correlation of High Fe-ContentFe-B-Si-Hf Bulk Glassy Alloys. Acta Metall Sin, 2017, 53(3): 369-375.
Fe-based amorphous alloys are well known for their good magnetic properties. But these alloys were only prepared into ribbon form in early times due to their insufficient glass-forming abilities (GFAs). After first synthesized of Fe-(Al, Ga)-P-C-B bulk glassy alloy, many Fe-based bulk metallic glasses (BMGs) were synthesized. Compared with amorphous alloy ribbons, the GFA of these alloys was significantly improved, but the saturation magnetization (Bs) was less than 1.5 T. To achieve higher Bs in Fe-based amorphous alloys, the Fe content should be maximized and the metalloid and alloying elements contents should be minimized, but it makes glass formation difficult. It is difficult to reveal the effect mechanism of Fe atoms in high Fe-content amorphous alloys, due to the complexity of the amorphous structure. The present work focuses on explores the structure-property correlations of high Fe-content Fe-B-Si-Hf multi-component glassy alloys with an amorphous structure model. A series of high Fe-content alloys with the composition of [Si-B2Fe7.7Hf0.3]Fe+Fex (x=0, 1.5, 2, 2.5 and 3) was produced by adding Fe atoms to the ideal cluster formula, which is based on the composition with the best glass-forming ability of [Si-B2Fe7.7Hf0.3]Fe (Fe72.5B16.7Si8.3Hf2.5) for Fe-B-Si-Hf quaternary alloys. Liquid quench, thermal analysis and magnetic measurement results show that the critical rod size for glassy alloys gradually decreases from 2.5 mm to 1 mm as the number of Fe atoms increases from 0 to 2. The [Si-B2Fe7.7Hf0.3]Fe+Fe2 (Fe76.4B14.3Si7.1Hf2.2) bulk glassy alloy has a high saturation magnetization of 1.58 T and a low coercive force of 2.8 A/m. The decreasing of the glass transition temperature, the thermal stability, the glass-forming ability and the Curie temperature with increasing Fe content in Fe-B-Si-Hf glassy alloys was evaluated using a “dual-cluster” ({[Si-B2Fe7.7Hf0.3]+[Fe-Fe14]x/15}Fe) amorphous structure model. The result shows that the [Fe-Fe14] cluster from the α-Fe phase plays an important role in determining the properties change for this series high Fe-content Fe-B-Si-Hf glassy alloys.
Fund: Supported by National Natural Science Foundation of China (Nos.51671045 and 51601073), National Magnetic Confined Fusion Energy Development (Nos.2013GB107003 and 2015GB105003) and Fundamental Research Funds for the Central Universities (No;DUT16ZD209)
Fig.1 XRD spectra of [Si-B2Fe7.7Hf0.3]Fe+Fex where x=0, 1.5 and 2 in rods with a critical dimension (dc) and x=2.5 and 3 in rods with 1 mm diameter (d) (a), and x=0, 1.5, 2, 2.5 and 3 in ribbons (b)
Fig.2 Bright field TEM image and the corresponding selected area electron diffraction (SAED) pattern (inset) of [Si-B2Fe7.7Hf0.3]Fe+Fe2 rod sample with diameter of 1 mm
Fig.3 DSC (a) and DTA (b) curves of [Si-B2Fe7.7Hf0.3]Fe+Fex (x=0, 1.5, 2, 2.5 and 3) glass ribbons (Tc—Curie temperature, Tg—glass transition temperature, Tx—onset crystallization temperature, Tl—liquidus temperature)
Fig.4 Variations of Tg, Tx and reduced glass transition temperature (Trg) against x in [Si-B2Fe7.7Hf0.3]Fe+Fex (x=0, 1.5, 2, 2.5 and 3) glass alloys
Fig.5 Magnetization vs the applied magnetic field (a) and the B-H loops (b) of the [Si-B2Fe7.7Hf0.3]Fe+Fex (x=0, 1.5, 2, 2.5 and 3) glass ribbons (B—magnetization, μ0—permeability of vacuum, H—magnetic field)
Fig.6 Variations of saturation magnetizations (Bs) and Curie temperature (Tc) against x in [Si-B2Fe7.7Hf0.3]Fe+Fex (x=0, 1.5, 2, 2.5 and 3) glass alloys
Cluster formulas
x
Corresponding
dc / mm
Tg / K
Tx / K
Tl / K
Trg
composition
[Si-B2Fe7.7Hf0.3]Fe+Fe0
0
Fe72.5B16.67Si8.3Hf2.5
2.5
852
885
1458
0.584
[Si-B2Fe7.7Hf0.3]Fe+Fe1.5
1.5
Fe75.6B14.8Si7.4Hf2.2
1.0
842
864
1472
0.572
[Si-B2Fe7.7Hf0.3]Fe+Fe2
2
Fe76.4B14.3Si7.1Hf2.2
1.0
824
847
1461
0.564
[Si-B2Fe7.7Hf0.3]Fe+Fe2.5
2.5
Fe77.2B13.8Si6.9Hf2.1
<1.0
830
852
1515
0.548
[Si-B2Fe7.7Hf0.3]Fe+Fe3
3
Fe78.0B13.3Si6.7Hf2.0
<1.0
825
849
1521
0.542
Table 1 Cluster formulas, corresponding compositions, critical size dc, Tg, Tx, Tl and Trg of [Si-B2Fe7.7Hf0.3]Fe+Fex (x=0, 1.5, 2, 2.5 and 3) glass alloys
Fig.7 2D schematic of amorphous structure for {[Si-B2Fe7.7Hf0.3]+[Fe-Fe14]x/15}Fe glassy alloys (The face center cubic-like array of [Si-B2(Fe, Hf)8] and [Fe-Fe14] atomic clusters are circled by black dotted lines, leaving behind the Fe glue atoms in the octahedral sites)
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