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低频电磁场作用下铝合金半连续铸造工艺与理论研究
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摘要
本文是国家重点基础研究发展规划资助项目(973)“提高铝材质量基础研究”中的部分内容,目的是开发一种大幅度提高铝合金铸锭质量的新型高效连铸技术。
    本文系统研究了低频电磁场对铝合金熔体凝固过程的影响,通过实验和理论分析首次指出低频电磁场能够有效提高溶质元素在基体中的固溶度,改善材料的微观组织。在理论分析与数值模拟的基础上,开发了低频电磁场作用下铝合金电磁铸造新工艺,获得了晶粒均匀细小、溶质元素偏析明显减弱及具有优良表面质量的7075 铝合金半连续铸锭,彻底消除了裂纹、表面偏析瘤等铸造缺陷。
    导出了低频电磁场作用下凝固前沿枝晶间熔体遵守的磁流体动力学方程,指出枝晶间熔体局部自然对流相关的溶质浓度起伏存在由温度梯度与枝晶间距共同决定的固有频率,处于该频率区间的电磁力振荡分量对枝晶间熔体的局部对流产生的影响得到增强,通过调节电磁场频率至相应区间,可以在较低的电磁场强度下,使电磁场的作用效果显著增强,对材料的微观组织和溶质元素的分布产生显著的影响。
    在Al-Cu 二元合金连续凝固过程中施加低频电磁场,发现在排除Lorentz 力时间平均值有旋分量引发的液相区熔体宏观流动的条件下,低频电磁场仍对铝合金的凝固过程产生了显著的影响,晶内析出相的尺寸和形态出现了明显的转变、基体中溶质元素固溶度提高。在保持电磁场强度不变的条件下,当电磁场频率处于10 Hz-15 Hz 范围内时,基体中溶质元素固溶度大幅度提高,获得了弥散细小的晶内析出相,这表明交变电磁力在与两相区中枝晶间熔体产生交互作用的过程中存在共振响应现象,在共振频率区间上,较低强度的电磁场便能够有效促进溶质元素的固溶、改善材料的微观组织。
    采用有限元数值模拟的方法分析了电磁场在铝合金半连续铸造过程中对熔体内部流动场、温度场及铸锭内应力分布情况的影响。结果表明,半连续铸造过程中结晶器、感应线圈与铸锭的相对位置,结晶器的断面形状与电导率,共同决定
This research is supported by the program of quality improvement of aluminum products, which is a part work of Major State Basic Research Projects of China. The ultimate aim is to develop a highly efficient technique by which the quality of the continuous casting ingot of aluminum alloys can be substantially improved.
    Influences of low-frequency electromagnetic field on solidification process of aluminum alloys are experimentally and theoretically studied in this paper. For the first time, make a point that the low-frequency electromagnetic field can effectively promote the solution of alloying elements, and refine the microstructures. A new technique for continuous casting of aluminum alloys by application of low-frequency electromagnetic field is developed, by which 7075 aluminum alloy ingot is produced, the fine equiaxed as-cast structures is obtained and surface quality is remarkably improved.
    The magnetohydrodynamic equations describing the behavior of interdendritic liquid in directional solidification process of aluminum alloy in the presence of low-frequency electromagnetic field is achieved. The equations indicate the existence of eigenfrequency determined by dendritic arm spacing and temperature gradient. When oscillatory component of Lorentz force in the range of eigenfrequency, resonance effect occurs and local compositional convection of interdendritic liquid is greatly enhanced.
    The effect of low-frequency electromagnetic field on solute distribution in directionally solidified Al-Cu binary alloy is investigated experimentally. It is found that excluding the influence of rotary component of Lorentz force, electromagnetic field substantially modified the distribution of alloying element, when frequency is in the range of 10 Hz-15 Hz, solution of alloying element in matrix is greatly promoted, and fine dispersed precipitates is obtained. The results reveal that the resonance effect plays
    a significant role in interaction between Lorentz force and compositional convection of interdendritic liquid, adopting eigenfrequency, the electromagnetic field with relative low intensity can effectively improve the microstructure of materials. Effect of electromagnetic field on flow pattern, temperature field and distribution of thermal stress in continuous casting process of aluminum alloy is numerically studied. The results show that the distribution of magnetic flux density vector in the air and melt is determined by density and frequency of coil current, shapes and locations of mold and melt. Intensity of magnetic field in the melt and ingot rapidly declines with increase of depth because of skin effect, and cannot be efficiently strengthened by increase the intensity of coil current. On the other hand, frequency greatly influences the pattern of magnetic flux density in melt and ingot. Alternating current generates a time varying magnetic field in the melt, which, in turn, gives rise to an induced current in melt and ingot. Therefore, the melt is subjected to electromagnetic body forces caused by the interaction of the induced current and the magnetic field. Under the effect of Lorentz force, the ideal flow pattern in the melt will be achieved, when the overheated melt can be driven from center region of the melt to the periphery more effective, and the depth of the sump will be decreased under the same casting speed. When frequency is higher than 50 Hz, vortex core position of forced convection mainly near the periphery of ingot, intensity of convection at center region or melt is relatively weak, and cannot be enhanced by increase of the intensity of coil current. Under the certain intensity of electromagnetic field, the flow pattern of the melt and therefore, the temperature field in the sump can be effectively modified by application of various frequencies, and when
    frequency reach the range of 25 Hz to 30 Hz, minimum depth of the sump is achieved. Thermal stresses in solidifying ingot present complex situation, because of reduction of temperature gradient and the decrease of sump depth in the presence of electromagnetic field, the stress intensity substantially decreases at the same time, the crack possibility greatly reduces accordingly. 7075 aluminum alloy ingot with diameter of 100 mm and 200 mm respectively are prepared by application of newly developed electromagnetic casting technique. Constrained effect of electromagnetic force results in the formation of a convex surface meniscus, and reduces the height of contact line between the mold and the melt, which, in turn, reduces the primary cooling intensity. Electromagnetic forced convection carries the detached side branch into the melt, broadens the mushy zone and promote the heterogeneous nucleation, decreases the height and the depth of the sump, reduced the temperature gradient. Low-frequency electromagnetic field is more effective in grain refinement and, at the same time significantly promotes the solution of alloying elements. When frequency is in the range of 15 to 20 Hz, fine-grained equiaxed microstructure is obtained. Frequency, as a principal parameter in electromagnetic casting process, greatly influences large-scale distribution of alloying elements. When frequency of alternating current reaches 30 Hz, surface exudation and center region segregation are inhibited effectively; distribution of alloying elements over the cross-section of ingot is relatively homogeneous. The result reveals that this new technique is a significant advancement for those aluminum alloys that are difficult to be
引文
1. Boettinger W J, Coriell S R, Greer A L, Karma A, Kurz W, Rappaz M, Trivedi R. Solidification microstructures: recent developments, future directions[J], Acta materialia, 2000, 48: 43-70.
    2. 周尧和,胡壮麒,介万奇. 凝固技术[M],北京:机械工业出版社,1998,445-466.
    3. 王晖,任忠鸣,蒋国昌. 均恒强磁场在材料科学中的应用[J],材料科学与工程,2001,19(2):119-125.
    4. 李廷举,温斌,张志峰,金俊泽. 电磁场作用下材料加工新技术[J],大连理工大学学报,2000,40(12):61-64.
    5. 张军,傅恒志,谢发勤,沈军,李建国. 金属熔体的电磁成形与凝固[J],材料研究学报,1997,11(12):612-622.
    6. Misra A K. A novel solidification technique of metals and alloys: under the influence of applied potential[J], Metallurgical Transactions, 1985, 16A: 1354-1355.
    7. Radjai A, Miwa K, Nishio T. An investigation of the effects caused by electromagnetic vibrations in a hypereutectic Al-Si alloy melt[J], Metallurgical and Materials Transactions, 1998, 29A: 1477-1484.
    8. Oreper G M, Szekely J. The effect of an externally imposed magnetic field on buoyancy driven flow in a rectangular cavity[J], Journal of Crystal Growth, 1983, 64: 505-515.
    9. Viv ès C, Perry C. Effects of magnetically damped convection during the controlled solidification of metals and alloys[J], International Journal of Heat and Mass Transfer, 1987, 30(3): 479-496.
    10. Li F, Regel L L, Wilcox W R. The influence of electric current pulses on the microstructure of the MnBi/Bi eutectic[J], Journal of Crystal Growth, 2001, 223: 251-264.
    11. Nakada M, Shiohara Y, Flemings M C. Modification of solidification structures by pulse electric discharging[J], ISIJ International, 1990, 30:27-33.
    12. Volz M P, Mazuruk K. Thermoconvective instability in a rotating magnetic field[J], International Journal of Heat and Mass Transfer, 1999, 42: 1037-1045.
    13. Alboussiere T, Neurand A C, J. Garandet P, Moreau R. Segregation during horizontal Bridgman growth under an axial magnetic field[J], Journal of Crystal Growth, 1997, 181: 133-144.
    14. Walker J S. Bridgman crystal growth with a strong, low-frequency, rotating magnetic field[J], Journal of Crystal Growth, 1998, 192: 318-327.
    15. Cho Y W, Chung S H, Shim J D, Dementev S, Ivanov S. Fluid flow and heat transfer in molten metal stirred by a circular inductor[J], International Journal of Heat and Mass Transfer, 1999, 42: 1317-1326.
    16. Levdansky V V, Kim H Y, Kim H C, Smolik J, Moravec P. Effect of electromagnetic field on transfer processes in heterogeneous systems[J], International Journal of Heat and Mass Transfer, 2001, 44: 1065-1071.
    17. Bingtao Z I, Qixian B A, Jianzhong C U I, Guangming X U. Study on axial changes of as-cast structures of Al-alloy sample treated by the novel SPMF technique[J], Scripta Materialia, 2000, 43: 377-380.
    18. Choi J, Ohtauka H, Xu Y, Choo W. Effect of a strong magnetic field on the phase stability of plain carbon steels[J], Scripta Materialia, 2000, 43: 221-226.
    19. Meyer J, Durand F, Ricou R, Vivès C. Steady flow of liquid aluminum in a rectangular-vertical ingot mold, thermally or electromagnetically activated[J], Metallurgical and Materials Transactions, 1984, 15B: 471-478.
    20. Li T, Nagaya S, Sassa K, Asal S. Study of meniscus behavior and surface properties during casting in a high-frequency magnetic field[J], Metallurgical and Materials Transactions, 1995, 26B: 353-359.
    21. Vivès C, Ricou R. Fluid flow phenomena in a single phase coreless induction furnace[J], Metallurgical Transactions, 1985, 16B: 227-235.
    22. Zheng X, Wang Y, Li Z, Jin J. Numerical simulation of the temperature field in the electromagnetic semi-continuous casting of slab[J], Science and Technology of Advanced
    Materials, 2001, 1: 109-111.
    23. Chandrasekhar R. Influence of magnetic field on sodium hexafluorosilicate synthesis[J], Journal of Crystal Growth, 2000, 216: 407-412.
    24. Coriell S R, Mcfadden G B, Billia B, Thi H N, Dabo Y. Electrical pulsing during directional solidification: analysis of transients by Laplace transform[J], Journal of Crystal Growth, 2000, 216: 495-500.
    25. Bessaih R, Kadja M, Marty P. Effect of wall electrical conductivity and magnetic field orientation on liquid metal flow in a geometry similar to the horizontal Bridgman configuration for crystal growth[J], International Journal of Heat and Mass Transfer, 1999, 42: 4345-4362.
    26. Shercliff J A. Thermoelectric magnetohydrodynamics[J], Journal of Fluid Mechanics, 1979, 91(2): 231-251.
    27. Hjellming L N, Tolley P A, Walker J S. Melt motion in a Czochralski crystal puller with a non-uniform axisymmetric magnetic field: isothermal motion[J], Journal of Fluid Mechanics, 1993, 249: 1-34.
    28. Alboussiere T, Garandet J P, Moreau R. Buoyancy-driven convection with a uniform magnetic field. Part 1. Asymptotic analysis[J], Journal of Fluid Mechanics, 1993, 253: 545-563.
    29. Pan B, Li B Q. Effect of magnetic fields on oscillating mixed convection[J], International Journal of Heat and Mass Transfer, 1998, 41: 2705-2710.
    30. 孝云祯,马宏声. 有色金属熔炼与铸锭[M],沈阳:东北大学出版社,1994,89-117.
    31. 路贵民,柯东杰. 铝合金熔炼理论与工艺[M],沈阳:东北大学出版社,1998,1-9.
    32. 胡文瑞. 宇宙磁流体力学[M],北京:科学出版社,1987,1-17.
    33. Moreau R. Magnetohydrodynamics[M], Dordrecht: Kluwer, 1990, 36-49.
    34. Hunt J C R. Magnetohydrodynamic flow in rectangular ducts[J], Journal of Fluid Mechanics, 1965, 21: 577-590.
    35. Kurz W, Fisher D J. Fundamentals of solidification[M], Switzerland: Transtech, 1984, 24-31.
    36. Holmes D E, Gatos H C. Morphological stability of the planar solid-liquid interface[J], Journal of Applied Physics, 1981, 52(4): 2971-2982.
    37. Aziz M J. Model for solute redistribution during rapid solidification[J], Journal of Applied Physics, 1982, 53(2): 1158-1168.
    38. Coriell S R, Parker R L. Role of surface diffusion in stabilizing the surface of a solid growing from solution or vapor[J], Journal of Applied Physics, 1966, 37(4): 1548-1551.
    39. Coriell S R, Parker R L. Stability of the shape of a solid cylinder growing in a diffusion field[J], Journal of Applied Physics, 1965, 36(2): 632-637.
    40. Trivedi R. Theory of dendritic growth during the directional solidification of binary alloys[J], Journal of Crystal Growth, 1980, 49: 219-232.
    41. Mullins W W, Sekerka R F. Morphological stability of a particle growing by diffusion or heat flow[J], Journal of Applied Physics, 1963, 34(2): 323-329.
    42. Tiller W A, Jackson K A, Rutter J W, Chalmers B. The redistribution of solute atoms during the solidification of metals[J], Acta Metallurgica, 1953, 1: 428-437.
    43. Huppert H E, Worster M G. Dynamic solidification of a binary melt[J], Nature. 1985, 314(25): 703-707.
    44. Hansen G, Hellawell A, Lu S Z, Steube R S. Some consequences of thermosolutal convection: the grain structure of castings[J], Metallurgical and Materials Transactions, 1996, 27A: 569-581.
    45. Li B Q, Anyalebechi P N. A micro/macro model for fluid flow evolution and microstructure formation in solidification processes[J], International Journal of Heat and Mass Transfer, 1995, 38(13): 2367-2381.
    46. Trivedi R, Miyahara H, Mazumder P, Simsek E, Tewari S N. Directional solidification microstructures in diffusive and convective regimes[J], Journal of Crystal Growth, 2001, 222: 365-379.
    47. Vaerenbergh S V, Coriell S R, Mcfadden C B. Morphological stability of a binary alloy: thermodiffusion and temperature-dependent diffusivity[J], Journal of Crystal Growth, 2001, 223: 565-572.
    48. Huppert H E. The fluid mechanics of solidification[J], Journal of Fluid Mechanics, 1990, 212: 209-240.
    49. Davis S H. Hydrodynamic interactions in directional solidification[J], Journal of Fluid Mechanics, 1990, 212: 241-262.
    50. Ma J, Wang B. The penetration rate of solid-liquid phase-change heat transfer interface with different kinds of boundary conditions[J], International Journal of Heat and Mass Transfer, 1995, 38(13): 2135-2138.
    51. Witzke S, Riquet J P, Durand F. Diffusion field ahead of a growing columnar front: Discussion of the columnar-equiaxed transition[J], Acta Metallurgica, 1981, 29: 365-374.
    52. Lipton J, Kurz W, Heinemann W. Modeling columnar to equiaxed transition[J], Contenst Technology, 1986, 22: 4-6.
    53. Fredriksson H, Olsson A. Mechanism of transition from columnar to equiaxed zone in ingots[J], Materials Science and Technology, 1986, 2: 508-516.
    54. Flemings M C. Principles of control of soundness and homogeneity of large ingots[J], Scand Journal Metallurgy, 1967, 5: 1-15.
    55. Flemings M C, Nereo G E. Macrosegregation[J], TMS-AIME. 1967, 239: 1449-1261.
    56. Ridder S P, Kou S, Mehrabian R. Effect of fluid flow on macrosegregation in axi-symmetric ingots[J], Metallurgical and Materials Transactions, 1987, 12B: 435-447.
    57. Ppirier D R. Permeability for flow of interdendritic liquid in columnar-dendritic alloys[J], Metallurgical Transactions, 1987, 18B: 245-255.
    58. Murakami K, Shiraiski A, Okamoto T. Interdendritic fluid flow normal to primary dendrite-arms in cubic alloys[J], Acta Metallurgica, 1983, 31:1417-1424.
    59. Murakami K, Shiraiski A, Okamoto T. Fluid flow in interdendritic spacing in cubic alloys[J], Acta Metallurgica. 1984, 32:1423-1428.
    60. Marsh S P, Glicksman M E. Overview of geometric effects on coarsening of mushy zones[J], Metallurgical and Materials Transactions, 1996, 27A: 557-567.
    61. Smith D M, Eady J A, Hogan L M, Irwin D W. Crystallization of a faceted primary phase in a stirred slurry[J], Metallurgical Transactions, 1991, 22A: 575-584.
    62. Nastac L, Stefanescu D M. Macrotransport-solidification kinetics modeling of equiaxed dendritic growth: part 1. Model development and discussion[J], Metallurgical and Materials Transactions, 1996, 27A: 4061-4074.
    63. Wang C Y, Beckermann C. Equiaxed dendritic solidification with convection: part 2. Numerical simulations for an Al-4 Wt Pct Cu alloy[J], Metallurgical and Materials Transactions, 1996, 27A: 2765-2783.
    64. Alexandrov D V. Solidification with a quasiequilibrium mushy region: exact analytical solution of nonlinear model[J], Journal of Crystal Growth, 2001, 222: 816-821.
    65. Cantor B, Vogel A. Dendritic solidification and fluid flow[J], Journal of Crystal Growth, 1977, 41: 109-123.
    66. Yan X, Xie F, Chu M, Chang Y A. Microsegregation in AI-4.5Cu wt.% alloy: experimental investigation and numerical modeling[J], Materials Science and Engineering, 2001, 302: 268-274.
    67. Zeisler-mashl K L, Lograsso T A. The occurrence and periodicity of oscillating peritectic microstructure developed during directional solidification[J], Metallurgical and Materials
    Transactions, 1997, 28A: 1543-1552.
    68. Prasso D C, Evans J W, Wilson I J. Heat transport and solidification in the electromagnetic casting of aluminum alloys: part 2. Development of a mathematical model and comparison with experimental results[J], Metallurgical and Materials Transactions, 1995, 26B: 1281-1288.
    69. Coriell S R, Murray B T, Chernov A A, McFadden G B. Effects of shear flow and anisotropic kinetics on the morphological stability of a binary alloy[J], Metallurgical and Materials Transactions, 1996, 27A: 687-694.
    70. Lee S L, Sheu S R. A new numerical formulation for incompressible viscous free surface flow without smearing the free surface[J], International Journal of Heat and Mass Transfer, 2001, 44: 1837-1848.
    71. Pompe O, Rettenmayr M. Microstructural changes during quenching[J], Journal of Crystal Growth, 1998, 192: 300-306.
    72. Dupouy M D, Drenet B, Camel D. Influence of convection on the selection of solidification microstructures at low growth rates[J], Journal of Crystal Growth, 1997, 181: 145-159.
    73. Nastac L. Analytical modeling of solute redistribution during the initial unsteady unidirectional solidification of binary dilute alloys[J], Journal of Crystal Growth, 1998, 193: 271-284.
    74. Shiah S W, Yang B C, Cheung F B, Shih Y C. Natural convection mass transfer along a dissolution boundary layer in an isothermal binary metallic system[J], International Journal of Heat and Mass Transfer, 1998, 41: 3759-3769.
    75. Lan C W, Yang D T. Dynamic simulation of the vertical zone-melting crystal growth[J], International Journal of Heat and Mass Transfer, 1998, 41: 4351-4373.
    76. Perepezko J H, Uttormark M J. Nucleation-controlled Solidification Kinetics[J], Metallurgical and Materials Transactions, 1996, 27A: 533-547.
    77. Quaresma J M V, Santos C A, Garcia A. Correlation between unsteady-state solidification conditions, dendrite spacings, and mechanical properties of Al-Cu alloys[J], Metallurgical and Materials Transactions, 2000, 31A: 3167-3178.
    78. Hunt J D, Lu S Z. Numerical modeling of cellular/dendritic array growth: spacing and structure predictions[J], Metallurgical and Materials Transactions, 1996, 27A: 611-623.
    79. Rappaz M, Gandin C A, Desbiolles J L, Thevoz P. Prediction of grain structures in various solidification process[J], Metallurgical and Materials Transactions, 1996, 27A: 695-705.
    80. Ni J, Incropera F P. Extension of continuum model for transport phenomena occurring during metal alloy solidification 1 the conservation equations[J], International Journal of Heat and
    Mass Transfer, 1995, 38: 1271-1284.
    81. Ni J, Incropera F P. Extension of continuum model for transport phenomena occurring during metal alloy solidification 2 microscopic considerations[J], International Journal of Heat and Mass Transfer, 1995, 38: 1285-1296.
    82. Kurz W, Trivedi R. Banded solidification microstructures[J], Metallurgical and Materials Transactions, 1996, 27A: 625-634.
    83. Aziz M J. Interface attachment kinetics in alloy solidification[J], Metallurgical and Materials Transactions, 1996, 27A: 671-686.
    84. Voller V R. A similarity solution for the solidification of a multicomponent alloy[J], International Journal of Heat and Mass Transfer, 1997, 40: 2869-2877.
    85. Paradies C J, Smith R N, Glicksman M E. The influence of convection during solidification on fragmentation of the mushy zone of a model alloy[J], Metallurgical and Materials Transactions, 1997, 28A: 875-883.
    86. Davis S H, Schulze T P. Effect of flow on morphological stability during directional solidification[J], Metallurgical and Materials Transactions, 1996, 27A: 583-593.
    87. Yoo H, Viskanta R. Solute redistribution limit in coarsening dendrite arms during binary alloy solidification[J], International Journal of Heat and Mass Transfer, 1997, 40(16): 3875-3882.
    88. Thevik H J, Mo A. The effect of macroscopic solute diffusion in the liquid upon surface macrosegregation[J], Metallurgical and Materials Transactions, 1997, 28B: 665-669.
    89. Singh A K, Bshu B. On convection in mushy phase and its effect on macrosegregation[J], Metallurgical and Materials Transactions, 2000, 31A: 1687-1692.
    90. Drezet J M, Rappaz M, Grun G U, Gremaud M. Determination of thermophysical properties and boundary conditions of direct chill-cast aluminum alloys using inverse methods[J], Metallurgical and Materials Transactions, 2000, 31A: 1627-1634.
    91. Reese J M. Characterization of the flow in the molten metal sump during direct chill aluminum casting[J], Metallurgical and Materials Transactions, 1997, 28B: 491-499.
    92. Baake E, Muhlbauer A, Jakowitsch A, Andree W. Extension of the k-εmodel for the numerical simulation of the melt flow in induction crucible furnaces[J], Metallurgical and Materials Transactions, 1995, 26B: 529-536.
    93. Reddy A V, Beckermann C. Modeling of macrosegregation due to thermosolutal convection and contraction-driven flow in direct chill continuous casting of an Al-Cu round ingot[J], Metallurgical and Materials Transactions, 1997, 28B: 479-489.
    94. Rousset P, Rappaz M, Hannart B. Modeling of inverse segregation and porosity formation in directionally solidified aluminum alloys[J], Metallurgical and Materials Transactions, 1995, 26A: 2349-2358.
    95. Tewari S N, Shah R. Macrosegregation during dendritic arrayed growth of hypoeutectic Pb-Sn alloys: influence of primary arm spacing and mushy zone length[J], Metallurgical and Materials Transactions, 1996, 27A: 1353-1362.
    96. Dobatkin V I, Anoshkin N F. Comparison of macrosegregation in titanium and aluminum alloy ingots[J], Materials Science and Engineering, 1999, A263: 223-229.
    97. Bennon W D, Incropera F P. A continuum model for momentum, heat and species transport in binary solid-liquid phase change systems---l. Model formulation[J], International Journal of Heat and Mass Transfer, 1987, 30(10): 2161-2170.
    98. Huang W, Inatomi Y, Kuribayashi K. Initial transient solute redistribution during directional solidification with liquid flow[J], Journal of Crystal Growth, 1997, 182: 212-218.
    99. Vreeman C J, Incropera F P. The effect of free-floating dendrites and convection on macrosegregation in direct chill cast aluminum alloys Part 2: predictions for Al-Cu and Al-Mg alloys[J], International Journal of Heat and Mass Transfer, 2000, 43: 687-704.
    100. Lan X K, Khodadadi J M. Fluid flow, heat transfer and solidification in the mold of continuous casters during ladle change[J], International Journal of Heat and Mass Transfer, 2001, 44: 953-965.
    101. Vreeman C J, Krne M J M, Incropera F P. The effect of free-floating dendrites and convection on macrosegregation in direct chill cast aluminum alloys Part 1: model development[J], International Journal of Heat and Mass Transfer, 2000, 43: 677-686.
    102. Garandet J P, Corre S, Kaddeche S, Alboussiere T. The influence of convection on the duration of the initial solute transient in alloy crystal growth[J], Journal of Crystal Growth, 2000, 209: 970-982.
    103. Bennon W D, Incropera F P. A continuum model for momentum, heat and species transport in binary solid-liquid phase change systems 2. Application to solidification in a rectangular cavity[J], International Journal of Heat and Mass Transfer, 1987, 30: 2171-2187.
    104. Zheng L L, Jr D J L, Zhang H. Role of thermotransport (Soret effect) in macrosegregation during eutectic/off-eutectic directional solidification[J], Journal of Crystal Growth, 1998, 191: 243-251.
    105. Schneider M C, Beckermann C. A numerical study of the combined effects of microsegregation, mushy zone permeability and flow, caused by volume contraction and thermosolutal convection, on macrosegregation and eutectic formation in binary alloy solidification[J], International Journal of Heat and Mass Transfer, 1995, 38(18): 3455-3473.
    106. Haug E, Mo A, Thevik H J. Macrosegregation near a cast surface caused by exudation and solidification shrinkage[J], International Journal of Heat and Mass Transfer, 1995, 38(9): 1553-1563.
    107. Thevik H J, Mo A. The influence of micro-scale solute diffusion and dendrite coarsening upon surface macrosegregation[J], International Journal of Heat and Mass Transfer, 1997, 40(9): 2055-2065.
    108. Kerr R C, Woods A W, Worster M G, Huppert H E. Disequilibrium and macrosegregation during solidification of a binary melt[J], Nature, 1989, 340, 357-362.
    109. Coriell S R, Mcfadder G B, Mitchell W F, Murray B T, Andrews J B, Arikawa Y. Effect of flow due to density change on eutectic growth[J], Journal of Crystal Growth, 2001, 224: 145-154.
    110. Kessler D. Sharp interface limits of a thermodynamically consistent solutal phase field model[J], Journal of Crystal Growth, 2001, 224: 175-186.
    111. Mortensen A. On the rate of dendrite arm coarsening[J], Metallurgical Transactions, 1991, 22A: 569-574.
    112. Yang W, Chen W, Chang K, Mannan S, Debarbadillo J. Freckle criteria for the upward directional solidification of alloys[J], Metallurgical and Materials Transactions, 2001, 32A: 397-406.
    113. Wang C Y, Beckermann C. A multiphase solute diffusion model for dendritic alloy solidification[J], Metallurgical Transactions, 1993, 24A: 2787-2802.
    114. Glicksman M E, Smith R N, Marsh S P, Krklinski R. Mushy zone modeling with microstructural coarsening kinetics[J], Metallurgical Transactions, 1992, 23A: 659-667.
    115. Wang C Y, Beckermann C. Equiaxed dendritic solidification with convection: part Ⅰ. Multiscale/multiphase modeling[J], Metallurgical and Materials Transactions, 1996, 27A: 2754-2764.
    116. Beckermann C, Wang C Y. Equiaxed dendritic solidification with convection: part Ⅲ. Comparisons with NH4Cl-H2O experiments[J], Metallurgical and Materials Transactions, 1996, 27A: 2784-2795.
    117. 单长智,王立娟,王德满. 实心圆锭的应力分析及防止裂纹的措施[J], 轻合金加工技术, 1997,25:1-4.
    118. 王恒林,郑贤淑,姚山,金俊泽. 热裂预测的等效应变判据[J], 大连理工大学学报,1998,38(3): 194-197.
    119. 杨秉俭,刘伟涛,苏俊义. 薄板坯连铸结晶器中铸坯凝固壳应力发展的有限元分析[J], 应用力学学报,1994,11(2): 55-62.
    120. 郑贤淑,金俊泽,李治. 厚大铸件热裂纹预测方法研究[J],大连理工大学学报,2000,40(3): 183-186.
    121. Lehmann P, Moreau R, Camel D, Bolcato R. Modification of interdendritic convection in directional solidification by a uniform magnetic field[J], Acta materialia, 1998, 46(11): 4067-4079.
    122. Riahi D N. Effects of a vertical magnetic field on chimney convection in a mushy layer[J], Journal of Crystal Growth, 2000, 216: 501-511.
    123. Branover H, Mestel A J, Moore D J, Shercliff J A. Magnetohydrodynamic flows and turbulence: a report on the Third Beer-Sheva Seminar[J], Journal of Fluid Mechanics, 1981,112: 487-497.
    124. Wright J, Yon S, Pozrikidis C. Numerical studies of two-dimensional faraday oscillations of inviscid fluids[J], Journal of Fluid Mechanics, 2000, 402:1-32.
    125. Loper D E. On the boundary conditions at a mush-melt interface[J], Journal of Crystal Growth, 2001, 222: 655-666.
    126. Amberg G, Homsy G M. Nonlinear analysis of buoyant convection in binary solidification with application to channel formation[J], Journal of Fluid Mechanics, 1993, 252: 79-98.
    127. Chang S, Stefanescu D M. A model for macrosegregation and its application to Al-Cu castings[J], Metallurgical and Materials Transactions, 1996,27A: 2708-2721.
    128. Xu J, Yu D. Further examinations of dendritic growth theories[J], Journal of Crystal Growth, 2001, 222: 399-413.
    129. Bergman M I, Fearn D R, Bloham J. Suppression of channel convection in solidifying Pb-Sn alloys via an applied magnetic field[J], Metallurgical and Materials Transactions, 1999, 30A: 1809-1815.
    130. Hurle D T, Jakeman E, Johnson C P. Convective temperature oscillations in molten gallium[J], Journal of Fluid Mechanics, 1974, 64(3): 565-576.
    131. Utrch H P, Flemings M. Elimination of solute banding in indium antimonide crystals by growth in a magnetic field[J], Journal of Applied Physics, 1966, 37(5): 2021-2024.
    132. Misra A K. A novel solidification technique of metals and alloys: under the influence of applied potential[J], Metallurgical Transactions, 1985, 16A: 1354-1355.
    133. Misra A K. Effect of electric potentials on solidification of near eutectic Pb-Sb-Sn alloy[J], Materials Letters, 1986, 4:176-177.
    134. Nakada M, Shiohara Y, Flemings M C. Modification of solidification structures by pulse electric discharging[J], ISIJ international, 1990, 30: 1691-1694.
    135. Nagai J. Steel flow control in a high-speed continuous slab caster using an electromagnetic brake[J], Iron & Steel Engineer, 1984, 61: 41.
    136. 李宝宽,赫冀成,贾光霖. 薄板坯连铸结晶器内钢液流场电磁制动的模拟研究[J], 金属学报,1997, 33(11): 1207.
    137. Tagawa T, Ozoe H. The natural convection of liquid metal in a cubical enclosure with various electroconductivities of the wall under the magnetic field[J], International Journal of Heat and Mass Transfer, 1998, 41: 1917-1928.
    138. Beitelman L. Effect of mold EMS design on billet casting productivity and product quality[J], Canadian Metallurgical Quarterly, 1999, 38 (5): 301-309.
    139. Spitzer K H, Reiter G, Schwerdtfeger K. Multi-Frequency Electromagnetic Stirring of Liquid Metals[J], ISIJ International, 1996, 36 (5): 487-492.
    140. Birat J P, Chone J. Electromagnetic Stirring on Billet, Bloom, and Slab Continuous Casters: State of Art in 1982[J], Ironmaking and Steelmaking, 1983, 110(6): 269-281.
    141. 严珩志,钟掘,毛大恒,赵啸林. 电磁场作用下铝及其合金的凝固结晶行为[J], 中国有色金属学报,1996,6(3): 158-159.
    142. Getselev Z V. Casting in an electromagnetic field[J], Journal of Metals, 1971, 23(10): 38.
    143. Lavers J D, Bringer P P. Electromagnetic transport and confinement of liquid metals[J], IEEE Transactions on Magnetics, 1989, 25(3): 495.
    144. Vivès C, Ricou R. Experimental study of continuous electromagnetic casting of aluminum alloy[J], Metallurgical Transactions, 1985, 16B: 377-384.
    145. Vivès C. Electromagnetic refining of aluminum alloys by the CERM process: part Ⅰ. working principle and metallurgical results[J], Metallurgical Transactions, 1989, 20B: 623-629.
    146. Vivès C. Electromagnetic refining of aluminum alloys by the CREM process: part Ⅱ. Specific practical problems and their solutions[J], Metallurgical Transactions, 1989, 20B: 631-643.
    147. Vivès C. Effects of forced electromagnetic vibrations during the solidification of Aluminum Alloys: Part 1. Solidification in the presence of crossed alternating electric fields and stationary magnetic fields[J], Metallurgical and Materials Transactions, 1996, 27B: 445-455.
    148. Vivès C. Effects of forced electromagnetic vibrations during the solidification of Aluminum Alloys: Part 2. Solidification in the presence of collinear variable and stationary magnetic fields[J], Metallurgical and Materials Transactions, 1996, 27B: 457-464.
    149. Zhu X R, Harding R A, Campbell J. Electromagnetic confinement including the dynamic effect due to melt flow[J], ISIJ International, 1999, 39(1): 1.
    150. El-Kaddah N, Szekely J. The electromagnetic force field, fluid field, and temperature profiles in levitated metal droplets[J], Metallurgical Transactions, 1983, 14B: 401-410.
    151. Meyer J L, El-Kaddah N, Szekely J. A comprehensive study of the induced current, the electromagnetic force field, and the velocity field in a complex electromagnetically driven flow system[J], Metallurgical Transactions, 1987, 18B: 529-538.
    152. Ilegbusi O J, Szekely J. Mathematical modeling of the electromagnetic stirring of molten metal-solid suspensions[J], Transactions ISIJ, 1988, 28: 97-102.
    153. Kolesnichenko A F, Podoltsev A D, Kucheryavaya I N. Action of pulse magnetic field on molten metal[J], ISIJ, 1994, 715-721.
    154. Tarapore E D, Evans J. Fluid velocity in induction melting furnaces: Part 1: Theory and laboratory experiments[J], Metallurgical Transactions, 1976, 7B: 343-351.
    155. Szekely J, Chang W. Turbulent electromagnetically driven flow in metals, Processing: Part 1 formulation[J], Ironmaking and Steelmaking, 1977, 3: 190-204.
    156. El-Kaddah N, Szekely J, Carlsson G. Fluid flow and mass transfer in an inductively stirred four-ton melt of melting steel: A comparison of measurements and predictions[J], Metallurgical Transactions, 1984, 15B: 633-640.
    157. Kim W S, Yoon J K. Numerical prediction of electromagnetically driven flow in ASEA-SKF ladle refining by straight induction stirrer[J], Ironmaking Steelmaking, 1991, 18(6): 425-432.
    158. Chung S I, Shin Y H, Yoon J. K. Flow characteristics by induction and gas stirring in ASEA-SKF ladles[J], ISIJ, 1992, 32(12): 1287-1296.
    159. Nathenson R D, Long L J, Hackworth D. T. Design of electromagnetic stirrers for continuous casting[J], Iron and steel engineer, 1986, 36-43.
    160. Spitzer K H, Dubke M, Schwerdtfeger K. Rotational electromagnetic stirring in continuous casting of round strands[J], Metallurgical Transactions, 1986, 17B: 119-131.
    161. Iwai K, Sassa K, Asai S. Theoretical analysis of the magnetic field of a cold crucible. Electromagnetic Forces and Applications[M], Amsterdam: Elsevier Science Publishers B.V., 1992, 263.

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