Solidification Microstructure and Wear Properties of Undercooled Cu-Co/Cu-Co-Fe Alloys Under a High Magnetic Field
WEI Chen, WANG Jun(), YAN Yujie, FAN Jiayi, LI Jinshan()
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
Cite this article:
WEI Chen, WANG Jun, YAN Yujie, FAN Jiayi, LI Jinshan. Solidification Microstructure and Wear Properties of Undercooled Cu-Co/Cu-Co-Fe Alloys Under a High Magnetic Field. Acta Metall Sin, 2024, 60(11): 1571-1583.
As functional metal materials, immiscible alloys demonstrate wide application prospects in industrial and electronic fields. Immiscible alloys with a uniformly distributed minority phase are a potential substitute for the materials applied in the manufacture of electric contactors and wear-resistant automotive components. Understanding the evolution of various microstructures of immiscible alloys and its correlation with their wear behavior is crucial for their industrial applications. Owing to the liquid-phase separation characteristics of binary Cu-Co and ternary Cu-Co-Fe immiscible alloys, segregation occurred or even a layered microstructure was formed by using conventional casting methods, and obtaining a uniform microstructure was difficult, which seriously limited their applications. This study presents a new strategy for inhibiting the liquid-phase separation and improving the properties of immiscible alloys. Under a high magnetic field, the microstructure of an undercooled alloy was changed, affecting its wear behavior. The experimental results reveal that the microstructures of Cu50Co50 and Cu52Co24Fe24 alloys showed dendritic morphology at modest undercooling without a magnetic field, while the microstructure of Cu50Co50 alloy exhibited a core-shell structure and Cu52Co24Fe24 alloy exhibited an eccentric core-shell structure under large undercooling. Moreover, the application of a high magnetic field resulted in the more uniform microstructure of Cu52Co24Fe24 alloy. With the application of a high magnetic field, the second phases generated by the phase separation of Cu50Co50 and Cu52Co24Fe24 alloys were elongated parallel to the magnetic field direction, and the size of second phases in the alloys decreased significantly in the perpendicular field direction, however, the microstructures of the Cu52Co24Fe24 alloy showed a more uniform distribution. Specimens with large undercoolings in Cu50Co50 and Cu52Co24Fe24 alloys exhibited excellent wear resistance regardless of the application of a high magnetic field. Any alloy that examined abrasive and adhesive wear mechanisms during the wear tests was characterized by rough surfaces generated by material detachment and parallel scratches in the sliding direction. Furthermore, the Cu52Co24Fe24 alloy has a high hardness and a relatively uniform distribution of microstructure under a magnetic field, resulting in the best wear resistance.
Fund: National Natural Science Foundation of China(52174375);National Natural Science Foundation of China(51690163);National Training Program of Innovation and Entrepreneurship for Undergraduates(S202210699088);Innovation Capability Support Program of Shaanxi Province(2020KJXX-073);Independent Project of State Key Laboratory of Solidification Processing(2023-TS-13)
Corresponding Authors:
WANG Jun, professor, Tel: (029)88460568, E-mail: nwpuwj@nwpu.edu.cn; LI Jinshan, professor, Tel: (029)88460568, E-mail: ljsh@nwpu.edu.cn
Fig.1 Schematic of solidification facility under the magnet
Fig.2 OM images of microstructures of the Cu50Co50 alloys solidified at different undercoolings (ΔT) and magnetic fields ( B ) (a-j) and secondary electron (SE) SEM images of the boxed regions in Figs.2a-j, respectively (a1-j1) (a, a1) 0 T, ΔT = 99 K (b, b1) 0 T, ΔT = 256 K (c, c1, d, d1) 5 T, ΔT = 133 K (e, e1, f, f1) 5 T, ΔT = 258 K (g, g1, h, h1) 10 T, ΔT = 116 K (i, i1, j, j1) 10 T, ΔT = 267 K
Fig.3 OM images of microstructures of the Cu52Co24Fe24 alloys solidified at different ΔT and magnetic fields (a-j) and SE-SEM images of the boxed regions in Figs.3a-j, respectively (a1-j1) (a, a1) 0 T, ΔT = 45 K (b, b1) 0 T, ΔT = 224 K (c, c1, d, d1) 5 T, ΔT = 86 K (e, e1, f, f1) 5 T, ΔT = 244 K (g, g1, h, h1) 10 T, ΔT = 110 K (i, i1, j, j1) 10 T, ΔT = 254 K
Fig.4 Worn surface morphologies of the Cu50Co50 alloy at different ΔT and magnetic fields (a-f) and corresponding enlarged images of boxed regions (a1-f1)
Fig.5 Worn surfaces morphologies of Cu52Co24Fe24 alloy at different ΔT and magnetic fields (a-f) and corresponding enlarged images of boxed regions (a1-f1)
Fig.6 Curves of friction coefficient vs time under different ΔT and magnetic fields of 0 T (a), 5 T (b) and 10 T (c), and average friction coefficients (d) of Cu50Co50 alloys (Inset in Fig.6a is the schematic of friction test)
Fig.7 Curves of friction coefficient vs time under different ΔT and magnetic fields of 0 T (a), 5 T (b) and 10 T (c), and average friction coefficients (d) of Cu52Co24Fe24 alloys (Inset in Fig.7a is the schematic of friction test)
Fig.8 Curves of friction coefficient vs time under different ΔT and magnetic fields of 0 T (a), 5 T (b), and 10 T (c) of Cu50Co50 and Cu52Co24Fe24 alloys
Fig.9 Microhardnesses of the Co-rich phase in Cu50Co50 and the Co, Fe-rich phase in Cu52Fe24Co24 alloys under different ΔT and magnetic fields
1
Uchida S, Kimura T, Nakamoto T, et al. Microstructures and electrical and mechanical properties of Cu-Cr alloys fabricated by selective laser melting [J]. Mater. Des., 2019, 175: 107815
2
Deng C K, Jiang H X, Zhao J Z, et al. Study on the solidification of Ag-Ni monotectic alloy [J]. Acta Metall. Sin., 2020, 56: 212
doi: 10.11900/0412.1961.2019.00192
Liu S C, Jie J C, Zhang J J, et al. A surface energy driven dissolution model for immiscible Cu-Fe alloy [J]. J. Mol. Liq., 2018, 261: 232
6
Zhao J Z, Li H L, Li H Q, et al. Microstructure formation in centrifugally cast Al-Bi alloys [J]. Comput. Mater. Sci., 2010, 49: 121
7
Liu S C, Jie J C, Guo Z K, et al. Solidification microstructure evolution and its corresponding mechanism of metastable immiscible Cu80Fe20 alloy with different cooling conditions [J]. J. Alloys Compd., 2018, 742: 99
8
Peng Y L, Wang Q, Wang N. A comparative study on the migration of minor phase globule in different-sized droplets of Fe-58wt.%Sn immiscible alloy [J]. Scr. Mater., 2019, 168: 38
9
Wu Y Q, Li C J. Investigation of the phase separation of Al-Bi immiscible alloy melts by viscosity measurements [J]. J. Appl. Phys., 2012, 111: 073521
10
Mullis A M, Jegede O E, Bigg T D, et al. Dynamics of core-shell particle formation in drop-tube processed metastable monotectic alloys [J]. Acta Mater., 2020, 188: 591
11
Zhang Y K, Gao J, Wei L L, et al. Novel insight into microstructural evolution of phase-separated Cu-Co alloys under influence of forced convection [J]. J. Mater. Sci., 2011, 46: 6603
12
Yang W, Chen S H, Yu H, et al. Effects of liquid separation on the microstructure formation and hardness behavior of undercooled Cu-Co alloy [J]. Appl. Phys., 2012, 109A: 665
13
Turchanin M A, Dreval L A, Abdulov A R, et al. Mixing enthalpies of liquid alloys and thermodynamic assessment of the Cu-Fe-Co system [J]. Powder Metall. Met. Ceram., 2011, 50: 98
14
Nakagawa Y. Liquid immiscibility in copper-iron and copper-cobalt systems in the supercooled state [J]. Acta Metall., 1958, 6: 704
15
Liu N, Liu F, Chen Z, et al. Liquid-phase separation in rapid solidification of undercooled Fe-Co-Cu melts [J]. J. Mater. Sci. Technol., 2012, 28: 622
16
Dai F P, Wang W L, Ruan Y, et al. Liquid phase separation and rapid dendritic growth of undercooled ternary Fe60Co20Cu20 alloy [J]. Appl. Phys., 2018, 124A: 20
17
Bai X J, Wang Y C, Cao C D. Metastable phase separation and rapid solidification of undercooled Co40Fe40Cu20 alloy [J]. Chin. Phys., 2018, 27B: 116402
18
Wei C, Wang J, He Y X, et al. Influence of high magnetic field on the liquid-liquid phase separation behavior of an undercooled Cu-Co immiscible alloy [J]. J. Alloys Compd., 2020, 842: 155502
19
Shuai S S, Wen S K, Guo R, et al. Research progress on solidification and nucleation of metals under magnetic fields [J]. Foundry Technol., 2022, 43: 699
Liu T, Wang Q, Yuan Y, et al. High-gradient magnetic field-controlled migration of solutes and particles and their effects on solidification microstructure: A review [J]. Chin. Phys., 2018, 27B: 118103
21
Martin J E, Venturini E, Odinek J, et al. Anisotropic magnetism in field-structured composites [J]. Phys. Rev., 2000, 61E: 2818
22
Yan Y J, Wei C, He Y X, et al. Effect of high magnetic field on solidification microstructure evolution of a Cu-Fe immiscible alloy [J]. China Foundry, 2022, 19: 335
23
Wei C, Li J S, Yan Y J, et al. Effect of high magnetic field on the microstructure evolution behavior of undercooled Cu-Co alloy [J]. Foundry Technol., 2022, 43: 180
He Y X, Li J S, Li L Y, et al. Magnetic-field-induced chain-like assemblies of the primary phase during non-equilibrium solidification of a Co-B eutectic alloy: Experiments and modeling [J]. J. Alloys Compd., 2020, 815: 152446
25
Shoji E, Isogai S, Suzuki R, et al. Neutron computed tomography of phase separation structures in solidified Cu-Co alloys and investigation of relationship between the structures and melt convection during solidification [J]. Scr. Mater., 2020, 175: 29
26
Wang J, He Y X, Li J S, et al. Experimental platform for solidification and in-situ magnetization measurement of undercooled melt under strong magnetic field [J]. Rev. Sci. Instrum., 2015, 86: 025102
27
Wei C, Wang J, He Y X, et al. Liquid-liquid phase separation in immiscible Cu-Co alloy [J]. Mater. Lett., 2020, 268: 127585
28
Wang W L, Hu L, Luo S B, et al. Liquid phase separation and rapid dendritic growth of high-entropy CoCrCuFeNi alloy [J]. Intermetallics, 2016, 77: 41
29
Sugioka K I, Inoue T, Kitahara T, et al. Study on the effect of melt convection on phase separation structures in undercooled CuCo alloys using an electromagnetic levitator superimposed with a static magnetic field [J]. Metall. Mater. Trans., 2014, 45B: 1439
30
Costa T A, Dias M, Freitas E S, et al. The effect of microstructure length scale on dry sliding wear behaviour of monotectic Al-Bi-Sn alloys [J]. J. Alloys Compd., 2016, 689: 767
31
Schouwenaars R, Jacobo V H, Ortiz A. Microstructural aspects of wear in soft tribological alloys [J]. Wear, 2007, 263: 727
32
Bowden F P, Leben L. The nature of sliding and the analysis of friction [J]. Proc. Roy. Soc., 1939, 169A: 371
33
Wang J, Li J S, Hu R, et al. Anomalous magnetism and normal field instability in supercooled liquid cobalt [J]. Appl. Phys. Lett., 2014, 105: 144101
34
Cruz K S, Meza E S, Fernandes F A P, et al. Dendritic arm spacing affecting mechanical properties and wear behavior of Al-Sn and Al-Si alloys directionally solidified under unsteady-state conditions [J]. Metall. Mater. Trans., 2010, 41A: 972
35
Wang M L, Lu Y P, Zhang G J, et al. A novel high-entropy alloy composite coating with core-shell structures prepared by plasma cladding [J]. Vacuum, 2021, 184: 109905
36
de Alfaia M Â O, Oliveira R, Lima T S, et al. Effects of cooling rate and microstructure scale on wear resistance of unidirectionally solidified Al-3.2wt.%Bi-(1; 3) wt.%Pb alloys [J]. Mater. Today Commun., 2020, 25: 101659
