金属合金凝固枝晶生长同步辐射实时成像研究
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摘要
同步辐射光源具有高能量、高亮度、高分辨率、单色性好等优点,其配合高读写速度及高分辨率的CCD成像系统,可实现对金属合金凝固过程的枝晶生长动态行为进行实时成像观察。本研究利用国内的北京同步辐射光源和上海同步辐射光源,对低熔点的Sn-12wt.%Bi合金的凝固进程中的枝晶生长、枝晶粗化以及在直流电场作用下的枝晶生长进行实时成像研究,成功地获得一系列丰富的等轴晶、柱状晶生长行为,如等轴晶-柱状晶转变、枝晶竞争生长、枝晶臂的断裂上浮等视频图像。通过得到的100gm厚的合金样品凝固的视频图像,解释了枝晶演变的动态过程,可以利用其对枝晶生长的动力学行为进行定量分析。
实验发现不同冷却速率和温度梯度下,发生的粗化机制不同。粗化主要发生在凝固的开始阶段,因此二次枝晶间距也决定于这个阶段。枝晶的合并主要发生在凝固的后期,而枝晶根部的重熔断裂多发生在低冷却速率下,1.5℃／min。在不同的温度梯度相同冷却速率下,从枝晶最初生成到达到最终二次枝晶间距的时间不同,但其最终的二次枝晶间距大致相同。合金枝晶生长的实时成像为验证枝晶粗化模型提供了有利的证据。
利用同步辐射成像对直流电场下Sn-Bi合金凝固时的枝晶生长过程进行实时观察。施加直流电场(电流密度7-32 A／cm2)后,枝晶生长受到抑制,枝晶尖端发生钝化成圆形或平直,并且没有发现三次枝晶的生成。随着电流密度的增加,枝晶形态发生了由柱状枝晶到胞状等轴晶再到枝晶状等轴晶的变化。特别地,当电流强度增大时,一次枝晶尖端发生分裂。
这些成像结果为验证或完善已有的金属合金凝固理论提供了直接的第一手实验数据。同步辐射X射线实时成像技术为研究金属合金凝固理论提供了崭新的实验手段和研究思路。
Dendrite growth in metallic alloy during solidification was observed by synchrotron radiation technique, which has high energy, high brightness, good monochromaticity, worked with high read and write speed and high resolution CCD system. Dendrite growth, dendrite coarsening, and dendrite growth under DC of Sn-12wt.%Bi alloy were studied at Beijing synchrotron radiation facility and Shanghai synchrotron radiation facility with an updated synchrotron radiation imaging technique. A series of growth behavior and morphology evolution of dendrite have been in situ observed, such as columnar-to-equiaxed transition, dendrite competition, and dendrite fragmentation & floating etc. The images obtained in 100μm thick samples reveal the dynamic process of dendrite growth and allow quantitative measurement and analysis.
It is shown by in situ observations that different coarsening mechanisms of secondary dendrite arm might operate under different cooling conditions or solidification stages. Coarsening mainly happened in early solidification stage realized by the competitions, and therefore, secondary dendrite arm spacing (DAS) is mainly determined in this stage. Coalescence was the dominant coarsening mechanism in late solidification stage. In particular, at lower cooling rate, e.g.1.5℃/min, dendrite fragmentation frequently occurred, and played an important role during dendrites coarsening. When alloy solidified at the same cooling rate with different temperature gradients, the time taken from the beginning of solidification to forming the final secondary arm spacing was different, but the final secondary arm spacing were almost same. The real time observations in real alloy can give direct proofs to verify the dendrite arm coarsening models.
Synchrotron radiation imaging technique was used to in situ observe the dendrite growth of a solidifying Sn-Bi binary alloy under a direct current (DC) electric field. By applying a DC (7-32 A/cm2), the dendrite branching was suppressed, the dendrite tip was modified to be round or flat, and no tertiary dendrite was found. With increasing DC density, the dendrite morphology was changed from columnar dendritic to equiaxed cellular to equiaxed dendritic. In particular, the primary dendrite branched following a tip-split manner in a higher intensity DC.
These results can offer the direct proofs to verify or improve the solidification theories of metallic alloy. This research opens a novel window to the study of alloy solidification and enables the unambiguous understanding of solidification processes in optically opaque, metallic alloys.
实验发现不同冷却速率和温度梯度下,发生的粗化机制不同。粗化主要发生在凝固的开始阶段,因此二次枝晶间距也决定于这个阶段。枝晶的合并主要发生在凝固的后期,而枝晶根部的重熔断裂多发生在低冷却速率下,1.5℃／min。在不同的温度梯度相同冷却速率下,从枝晶最初生成到达到最终二次枝晶间距的时间不同,但其最终的二次枝晶间距大致相同。合金枝晶生长的实时成像为验证枝晶粗化模型提供了有利的证据。
利用同步辐射成像对直流电场下Sn-Bi合金凝固时的枝晶生长过程进行实时观察。施加直流电场(电流密度7-32 A／cm2)后,枝晶生长受到抑制,枝晶尖端发生钝化成圆形或平直,并且没有发现三次枝晶的生成。随着电流密度的增加,枝晶形态发生了由柱状枝晶到胞状等轴晶再到枝晶状等轴晶的变化。特别地,当电流强度增大时,一次枝晶尖端发生分裂。
这些成像结果为验证或完善已有的金属合金凝固理论提供了直接的第一手实验数据。同步辐射X射线实时成像技术为研究金属合金凝固理论提供了崭新的实验手段和研究思路。
Dendrite growth in metallic alloy during solidification was observed by synchrotron radiation technique, which has high energy, high brightness, good monochromaticity, worked with high read and write speed and high resolution CCD system. Dendrite growth, dendrite coarsening, and dendrite growth under DC of Sn-12wt.%Bi alloy were studied at Beijing synchrotron radiation facility and Shanghai synchrotron radiation facility with an updated synchrotron radiation imaging technique. A series of growth behavior and morphology evolution of dendrite have been in situ observed, such as columnar-to-equiaxed transition, dendrite competition, and dendrite fragmentation & floating etc. The images obtained in 100μm thick samples reveal the dynamic process of dendrite growth and allow quantitative measurement and analysis.
It is shown by in situ observations that different coarsening mechanisms of secondary dendrite arm might operate under different cooling conditions or solidification stages. Coarsening mainly happened in early solidification stage realized by the competitions, and therefore, secondary dendrite arm spacing (DAS) is mainly determined in this stage. Coalescence was the dominant coarsening mechanism in late solidification stage. In particular, at lower cooling rate, e.g.1.5℃/min, dendrite fragmentation frequently occurred, and played an important role during dendrites coarsening. When alloy solidified at the same cooling rate with different temperature gradients, the time taken from the beginning of solidification to forming the final secondary arm spacing was different, but the final secondary arm spacing were almost same. The real time observations in real alloy can give direct proofs to verify the dendrite arm coarsening models.
Synchrotron radiation imaging technique was used to in situ observe the dendrite growth of a solidifying Sn-Bi binary alloy under a direct current (DC) electric field. By applying a DC (7-32 A/cm2), the dendrite branching was suppressed, the dendrite tip was modified to be round or flat, and no tertiary dendrite was found. With increasing DC density, the dendrite morphology was changed from columnar dendritic to equiaxed cellular to equiaxed dendritic. In particular, the primary dendrite branched following a tip-split manner in a higher intensity DC.
These results can offer the direct proofs to verify or improve the solidification theories of metallic alloy. This research opens a novel window to the study of alloy solidification and enables the unambiguous understanding of solidification processes in optically opaque, metallic alloys.
引文
[1]大野笃美.金属凝固学.北京：机械工业出版社,1983.1-2
[2]Young K P, Kirkwood D H. The dendrite arm spacings of alμminμm-copper alloys solidified under steady-state conditions. Metall. Trans. A,1975,6A:197-205
[3]Peterson P W, Kattamis T Z, Giamei A F. Coarsening kinetics during solidification of Ni-Al-Ta dendrite monocrystals. Metall. Trans. A,1980,11A:1059-1065
[4]Grugel R N. Secondary and tertiary dendrite arm spacing relationships in directionally solidified Al-Si alloys. J. Mater. Sci.1993,28:677-683
[5]Flemings M C, Kattamis T Z, Bardes B P. Dendrite arm spacing in alμminμm alloys. Trans. AFS, 1991,176:501-506
[6]介万奇,周尧和.柱状晶向等轴晶转变过程的模拟实验研究.西北工业大学学报,1988,6：29-40
[7]Grange G, Gastaldi J, Jourdan C, et al. Evolution of characteristic pattern parameters in directional solidification of thin sample of a dilute Al-Cu alloy. J. Cryst. Growth,1995,151:192-199
[8]朱鸣芳,戴挺,李成允,等.对流作用下枝晶生长行为的数值模拟.中国科学,E辑,2005.35：673-688
[9]朱鸣芳,于金,洪俊杓.金属凝固显微组织的计算机模拟.中国工程科学,2004,6：8-16
[10]朱昌盛,王智平,荆涛,‘等.对流影响枝晶生长的相场法模拟研究进展.材料导报,2004,18：26-28
[11]Lan C W, Hsu C M, Liu C C, et al. Adaptive phase field simulation of dendritic growth in a forced flow at various supercoolings. Phys Rev E,2002,65:061601
[12]许庆彦,熊守美,柳百成.铸造合金的微观组织模拟研究进展.材料导报,2002,16：11-14
[13]T6nhardt R, Amberg G. Dendritic growth of randomly oriented nuclei in a shear flow. J. Crystal Growth,2000,213:161-187
[14]冼鼎昌.同步辐射光源史话[J].现代物理知识,1992,1：12-14
[15]马礼敦,杨福家.同步辐射应用概论[M].上海：复旦大学出版社,2001
[16]冼鼎昌.同步辐射现状和发展[J].中国科学基金,2005,6：321-325
[17]吴苍生.同步辐射的特性和应用[J].物理,1985,1：1-7
[18]齐日迈拉图.同步辐射的特性[J].呼伦贝尔学院学报,2006,8：62-64
[19]唐福元.同步辐射的发现、特性及其应用领域的开拓[J].物理与工程,2004,3：34-38
[20]Mathiesen R H, Arnberg L. X-ray radiography observations of columnar dendritic growth and constitutional undercooling in an Al-30wt%Cu alloy [J].Acta Mat.,2005,53:947-956
[21]Bogno A, Nguyen-Thi H, Bergeon N, el at. Application of synchrotron X-ray radiography to the study of dendritic equiaxed microstructure formation in Al-Cu alloys [J].Nuclear instruments & methods in physics research section B-beam interactions with materials and atoms,2010,268: 394-398
[22]Mathiesen R H, Arnberg L. The real-time, high-resolution X-ray video microscopy of solidification in aluminum alloys [J]. Jom,2007,8:20-26
[23]Mathiesen R H, Arnberg L. Stray crystal formation in Al-20 wt.% Cu studied by synchrotron X-ray video microscopy [J]. Mater. Sci. Eng. A,2005,413-414:283-287
[24]Mathiesen R H, Arnberg L, Bleuet P, et al. Crystal fragmentation and columnar-to-equiaxed transitions in Al-Cu studied by synchrotron X-ray video microscopy [J]. Metall. Mater. Trans. A, 2006,37A:2515-2524
[25]Reinhart G, Mangelinck-Noel N, Nguyen-Thi H, et al. Investigation of columnar-equiaxed transition and equiaxed growthbof aluminium based alloys by X-ray radiography [J]. Mater. Sci. Eng. A,2005,413-414:384-388
[26]Yasuda H, Ohnaka I, Kawasaki K, et al. Direct observation of stray crystal formation in unidirectional solidification of Sn-Bi alloy by X-ray imaging [J]. J. Cryst. Growth,2004,262: 645-652
[27]Yasuda H, Yamamoto Y, Nakatsuka N, ea al. In situ observation of solidification phenomena in Al-Cu and Fe-Si-Al alloys [J]. Int. J. Cast Met. Res.,2009,22:15-21
[28]Mathiesen R H, Arnberg L, Rams0skar K, et al. Time-resolved X-ray imaging of aluminum alloy solidification processes [J]. Metall. Mater. Trans. B,2002,33B:613-623
[29]Schaffer P L, Mathiesen R H, Arnberg L. In-situ X-ray investigation of immiscible phases in Al-Bi alloys [J]. The Minerals, Metals& Materials Society,2006:283-289
[30]Schaffer P L, Mathiesen R H, Arnberg L. L2 droplet interaction witha-Al during solidification of hypermonotectic Al-8 wt.%Bi alloys[J]. Acta Mat.,2009,57:2887-2895
[31]Nguyen-Thi H, Gastaldi J, Schenk T, et al. In situ and real-time probing of quasicrystal solidification dynamics by synchrotron imaging [J]. Phys. Rev. E,2006,74:031605
[32]Gastaldi J, Schenk T, Reinhart G, et al. In situ observation of pore evolution during melting and solidification of Al-Pd-Mn quasicrystals by synchrotron X-ray radiography [J]. Phil. Mag.,2006, 86:335-340
[33]Snigirev A, Snigireva I, Kohn V, et al. On the possibilities of x-ray phase constrast microimaging by coherent high-energy synchrotron radiation [J]. Rev. Sci. Instrum.,1995,66:5486-5492
[34]陈博.X射线相位衬度成像相关光学问题研究[D].合肥：中国科学技术大学,2007
[35]朱佩平,袁清习,黄万霞,等.衍射增强成像原理[J].物理学报,2006,55：1089-1098
[36]黄万霞,袁清习,田玉莲,等.同步辐射硬X射线衍射增强成像新进展[J].物理学报,2005,54：677-681
[37]LaCombe J C, Koss M B, Glicksman M E. Nonconstant tip velocity in microgravity dendritic growth [J]. Phys. Rev. Lett,1999,83:2997-3000
[38]Kattamis T Z, Flemings M C. Dendrite structure and grain size of undercooled melts [J]. Trans. AIME.,1966,236:1523-1532
[39]Kattamis T Z, Coughlin J C, Flemings M C. Influence of coarsening on dendrite arm spacing of aluminum-copper alloys [J]. Trans. AIME.,1967,239:1504-1511
[40]Kahlweit M. On the ageing of dendrites [J]. Scripta Metall.,1968,2:251-254
[41]Young K P, Kirkwood DH. The dendrite arm spacings of aluminum-copper alloy solidified under steady-state conditions [J]. Metall. Trans. A.,1975,6A:197-205
[42]Flemings M C, Kattamis T Z, Bardes B P. Dendrite arm spacing in aluminum alloys [J].Trans AFS,1991,176:501-506
[43]Li B, Brody H D, and Kazimirov A. Real-time observation of dendrite coarsening in Sn-13%Bi alloy by synchrotron microradiography [J]. Phys. Rev. E.,2004,70:062602
[44]Li B, Brody H D, and Kazimirov A. Real time synchrotron microradiography of dendrite coarsening in Sn-13 wt pct Bi alloy [J]. Metall. Mater. Trans. A.,2007,38A:599-605
[45]Li B, Brody H D, and Kazimirov A. Synchrotron microradiography of temperature gradient zone melting in directional solidification [J]. Metall. Mater. Trans. A.,2006,37A:1039-1044
[46]Ruvalcaba D, Mathiesen R H, Eskin D G, et al. In-situ analysis of coarsening during directional solidification experiments in high-solute aluminum alloys [J]. Metall. Mater. Trans. B,2009,40: 312-316
[47]Pfann W G. Principles of field freezing [J]. Trans. Met. Soc. AIME,1962,224:1139-1145
[48]Misra A K. A novel solidification technique of metal and alloy:under the influence of applied potential [J]. Metall. Trans. A,1985,16A:1354-1355
[49]Misra A K. Misra technique applied to solidification of cast iron [J]. Metall. Trans. A,1986,17A: 358-360
[50]Ahmed S, Mckannan E C. Control of gamma morphology in nickel base super-alloys through alloy design and densification on processing under electric-field [J]. Mater. Sci. Technol.,1994, 10:941-946
[51]Prodhan A, Sivaramakrishnan C S, Chakrabarti A K. Solidification of aluminum in electric field [J]. Metall. Mater. Trans. B,2001,32:372-378
[52]王劲,尹建军,丁雨田,等.ZA27合金在直流电流作用下的凝固行为[J].甘肃工业大学学报,2003,29：36-38
[53]黄立国,张伟强.直流电场对Al-Si共晶合金凝固组织的影响[J].材料开发与应用,2005,20：8-10
[54]黄立国,张伟强.直流电场对Al-Cu共晶合金凝固组织的影响[J].材料工程,2004,10：36-41
[55]崔衡,苍大强,李玲珍,等.液态下施加直流电对工业纯铝凝固组织的影响[J].铸造技术,2006,27：729-731
[56]崔衡,苍大强,宗燕兵,等.电流处理细化纯铝凝固组织的研究[J].有色冶金设计与研究,2006,27：6-8
[57]李辉,边秀房,刘相法,等.电流处理对铝合金组织及性能的影响[J].特种铸造及有色合金,1996,3：8-10
[58]Nakada M, Shiohara Y, Flemings M C. Modification of solidification structure by pulse electric discharging [J]. ISIJ int.,1990,30:27-33
[59]Barnak J P, Sprecher A F, Conrad H. Colony (grain) size reduction in eutectic Pb-Sn castings by electroplusing [J]. Scripta. Metall.,1995,32:879-884
[60]Conrad H. Influence of an electric or magnetic field on the liquid-solid transformation in materials and on the microstructure of the solid [J]. Mater. Sci. Eng. A,2000,287:205-212
[61]赵志龙,刘林.ZL102铝硅合金的脉冲电变质处理及其对力学性能的影响[J].铸造,2005,54：892-894
[62]刘华泽,赵志龙,马连辉,等.高密度脉冲电流对纯铝凝固晶粒组织及其过冷度的影响[J].有色合金及其熔炼,2008,29：1354-1358
[63]唐波,严超,赵志龙,等.脉冲电流对Al-4%Cu合金铸造组织的细化作用[J].铸造技术,2005,26：306-308
[64]范金辉,李仁兴,候旭,等.不同参数脉冲电流对不锈钢1Cr18Ni9Ti凝固组织的影响[J].铸造技术,2003,24：534-536
[65]范金辉,华勤,候旭,等.脉冲电流对奥氏体不锈钢凝固的影响[J].钢铁,2003,38：44-46
[66]王建中,王静松,常国威,等.电脉冲孕育处理对连铸Q235钢小方胚凝固组织的影响[J].辽宁工学院学报,1999,19：1-4
[67]Chang G W, Yuan J P, Wang Z D, et al. Effect of electric current on stability of solidification interface morphology [J]. Trans. Nonferrous Met. Soc. China,2000,10:445-448
[68]Coriell S R, McFadden G B, Wheeler A A, et al. The effect of an electric flied on the morphological stability of the crystal-melt interface of a binary alloy:Ⅱ Joule heating and thermoelectric effects [J]. J.Cryst. Growth,1989,94:334-346
[69]Mullins W W, Sakerka R F. Stability of planar interface during solidification of dilute binary alloy [J]. J. Applied Phys.,1964,35:444-451
[2]Young K P, Kirkwood D H. The dendrite arm spacings of alμminμm-copper alloys solidified under steady-state conditions. Metall. Trans. A,1975,6A:197-205
[3]Peterson P W, Kattamis T Z, Giamei A F. Coarsening kinetics during solidification of Ni-Al-Ta dendrite monocrystals. Metall. Trans. A,1980,11A:1059-1065
[4]Grugel R N. Secondary and tertiary dendrite arm spacing relationships in directionally solidified Al-Si alloys. J. Mater. Sci.1993,28:677-683
[5]Flemings M C, Kattamis T Z, Bardes B P. Dendrite arm spacing in alμminμm alloys. Trans. AFS, 1991,176:501-506
[6]介万奇,周尧和.柱状晶向等轴晶转变过程的模拟实验研究.西北工业大学学报,1988,6：29-40
[7]Grange G, Gastaldi J, Jourdan C, et al. Evolution of characteristic pattern parameters in directional solidification of thin sample of a dilute Al-Cu alloy. J. Cryst. Growth,1995,151:192-199
[8]朱鸣芳,戴挺,李成允,等.对流作用下枝晶生长行为的数值模拟.中国科学,E辑,2005.35：673-688
[9]朱鸣芳,于金,洪俊杓.金属凝固显微组织的计算机模拟.中国工程科学,2004,6：8-16
[10]朱昌盛,王智平,荆涛,‘等.对流影响枝晶生长的相场法模拟研究进展.材料导报,2004,18：26-28
[11]Lan C W, Hsu C M, Liu C C, et al. Adaptive phase field simulation of dendritic growth in a forced flow at various supercoolings. Phys Rev E,2002,65:061601
[12]许庆彦,熊守美,柳百成.铸造合金的微观组织模拟研究进展.材料导报,2002,16：11-14
[13]T6nhardt R, Amberg G. Dendritic growth of randomly oriented nuclei in a shear flow. J. Crystal Growth,2000,213:161-187
[14]冼鼎昌.同步辐射光源史话[J].现代物理知识,1992,1：12-14
[15]马礼敦,杨福家.同步辐射应用概论[M].上海：复旦大学出版社,2001
[16]冼鼎昌.同步辐射现状和发展[J].中国科学基金,2005,6：321-325
[17]吴苍生.同步辐射的特性和应用[J].物理,1985,1：1-7
[18]齐日迈拉图.同步辐射的特性[J].呼伦贝尔学院学报,2006,8：62-64
[19]唐福元.同步辐射的发现、特性及其应用领域的开拓[J].物理与工程,2004,3：34-38
[20]Mathiesen R H, Arnberg L. X-ray radiography observations of columnar dendritic growth and constitutional undercooling in an Al-30wt%Cu alloy [J].Acta Mat.,2005,53:947-956
[21]Bogno A, Nguyen-Thi H, Bergeon N, el at. Application of synchrotron X-ray radiography to the study of dendritic equiaxed microstructure formation in Al-Cu alloys [J].Nuclear instruments & methods in physics research section B-beam interactions with materials and atoms,2010,268: 394-398
[22]Mathiesen R H, Arnberg L. The real-time, high-resolution X-ray video microscopy of solidification in aluminum alloys [J]. Jom,2007,8:20-26
[23]Mathiesen R H, Arnberg L. Stray crystal formation in Al-20 wt.% Cu studied by synchrotron X-ray video microscopy [J]. Mater. Sci. Eng. A,2005,413-414:283-287
[24]Mathiesen R H, Arnberg L, Bleuet P, et al. Crystal fragmentation and columnar-to-equiaxed transitions in Al-Cu studied by synchrotron X-ray video microscopy [J]. Metall. Mater. Trans. A, 2006,37A:2515-2524
[25]Reinhart G, Mangelinck-Noel N, Nguyen-Thi H, et al. Investigation of columnar-equiaxed transition and equiaxed growthbof aluminium based alloys by X-ray radiography [J]. Mater. Sci. Eng. A,2005,413-414:384-388
[26]Yasuda H, Ohnaka I, Kawasaki K, et al. Direct observation of stray crystal formation in unidirectional solidification of Sn-Bi alloy by X-ray imaging [J]. J. Cryst. Growth,2004,262: 645-652
[27]Yasuda H, Yamamoto Y, Nakatsuka N, ea al. In situ observation of solidification phenomena in Al-Cu and Fe-Si-Al alloys [J]. Int. J. Cast Met. Res.,2009,22:15-21
[28]Mathiesen R H, Arnberg L, Rams0skar K, et al. Time-resolved X-ray imaging of aluminum alloy solidification processes [J]. Metall. Mater. Trans. B,2002,33B:613-623
[29]Schaffer P L, Mathiesen R H, Arnberg L. In-situ X-ray investigation of immiscible phases in Al-Bi alloys [J]. The Minerals, Metals& Materials Society,2006:283-289
[30]Schaffer P L, Mathiesen R H, Arnberg L. L2 droplet interaction witha-Al during solidification of hypermonotectic Al-8 wt.%Bi alloys[J]. Acta Mat.,2009,57:2887-2895
[31]Nguyen-Thi H, Gastaldi J, Schenk T, et al. In situ and real-time probing of quasicrystal solidification dynamics by synchrotron imaging [J]. Phys. Rev. E,2006,74:031605
[32]Gastaldi J, Schenk T, Reinhart G, et al. In situ observation of pore evolution during melting and solidification of Al-Pd-Mn quasicrystals by synchrotron X-ray radiography [J]. Phil. Mag.,2006, 86:335-340
[33]Snigirev A, Snigireva I, Kohn V, et al. On the possibilities of x-ray phase constrast microimaging by coherent high-energy synchrotron radiation [J]. Rev. Sci. Instrum.,1995,66:5486-5492
[34]陈博.X射线相位衬度成像相关光学问题研究[D].合肥：中国科学技术大学,2007
[35]朱佩平,袁清习,黄万霞,等.衍射增强成像原理[J].物理学报,2006,55：1089-1098
[36]黄万霞,袁清习,田玉莲,等.同步辐射硬X射线衍射增强成像新进展[J].物理学报,2005,54：677-681
[37]LaCombe J C, Koss M B, Glicksman M E. Nonconstant tip velocity in microgravity dendritic growth [J]. Phys. Rev. Lett,1999,83:2997-3000
[38]Kattamis T Z, Flemings M C. Dendrite structure and grain size of undercooled melts [J]. Trans. AIME.,1966,236:1523-1532
[39]Kattamis T Z, Coughlin J C, Flemings M C. Influence of coarsening on dendrite arm spacing of aluminum-copper alloys [J]. Trans. AIME.,1967,239:1504-1511
[40]Kahlweit M. On the ageing of dendrites [J]. Scripta Metall.,1968,2:251-254
[41]Young K P, Kirkwood DH. The dendrite arm spacings of aluminum-copper alloy solidified under steady-state conditions [J]. Metall. Trans. A.,1975,6A:197-205
[42]Flemings M C, Kattamis T Z, Bardes B P. Dendrite arm spacing in aluminum alloys [J].Trans AFS,1991,176:501-506
[43]Li B, Brody H D, and Kazimirov A. Real-time observation of dendrite coarsening in Sn-13%Bi alloy by synchrotron microradiography [J]. Phys. Rev. E.,2004,70:062602
[44]Li B, Brody H D, and Kazimirov A. Real time synchrotron microradiography of dendrite coarsening in Sn-13 wt pct Bi alloy [J]. Metall. Mater. Trans. A.,2007,38A:599-605
[45]Li B, Brody H D, and Kazimirov A. Synchrotron microradiography of temperature gradient zone melting in directional solidification [J]. Metall. Mater. Trans. A.,2006,37A:1039-1044
[46]Ruvalcaba D, Mathiesen R H, Eskin D G, et al. In-situ analysis of coarsening during directional solidification experiments in high-solute aluminum alloys [J]. Metall. Mater. Trans. B,2009,40: 312-316
[47]Pfann W G. Principles of field freezing [J]. Trans. Met. Soc. AIME,1962,224:1139-1145
[48]Misra A K. A novel solidification technique of metal and alloy:under the influence of applied potential [J]. Metall. Trans. A,1985,16A:1354-1355
[49]Misra A K. Misra technique applied to solidification of cast iron [J]. Metall. Trans. A,1986,17A: 358-360
[50]Ahmed S, Mckannan E C. Control of gamma morphology in nickel base super-alloys through alloy design and densification on processing under electric-field [J]. Mater. Sci. Technol.,1994, 10:941-946
[51]Prodhan A, Sivaramakrishnan C S, Chakrabarti A K. Solidification of aluminum in electric field [J]. Metall. Mater. Trans. B,2001,32:372-378
[52]王劲,尹建军,丁雨田,等.ZA27合金在直流电流作用下的凝固行为[J].甘肃工业大学学报,2003,29：36-38
[53]黄立国,张伟强.直流电场对Al-Si共晶合金凝固组织的影响[J].材料开发与应用,2005,20：8-10
[54]黄立国,张伟强.直流电场对Al-Cu共晶合金凝固组织的影响[J].材料工程,2004,10：36-41
[55]崔衡,苍大强,李玲珍,等.液态下施加直流电对工业纯铝凝固组织的影响[J].铸造技术,2006,27：729-731
[56]崔衡,苍大强,宗燕兵,等.电流处理细化纯铝凝固组织的研究[J].有色冶金设计与研究,2006,27：6-8
[57]李辉,边秀房,刘相法,等.电流处理对铝合金组织及性能的影响[J].特种铸造及有色合金,1996,3：8-10
[58]Nakada M, Shiohara Y, Flemings M C. Modification of solidification structure by pulse electric discharging [J]. ISIJ int.,1990,30:27-33
[59]Barnak J P, Sprecher A F, Conrad H. Colony (grain) size reduction in eutectic Pb-Sn castings by electroplusing [J]. Scripta. Metall.,1995,32:879-884
[60]Conrad H. Influence of an electric or magnetic field on the liquid-solid transformation in materials and on the microstructure of the solid [J]. Mater. Sci. Eng. A,2000,287:205-212
[61]赵志龙,刘林.ZL102铝硅合金的脉冲电变质处理及其对力学性能的影响[J].铸造,2005,54：892-894
[62]刘华泽,赵志龙,马连辉,等.高密度脉冲电流对纯铝凝固晶粒组织及其过冷度的影响[J].有色合金及其熔炼,2008,29：1354-1358
[63]唐波,严超,赵志龙,等.脉冲电流对Al-4%Cu合金铸造组织的细化作用[J].铸造技术,2005,26：306-308
[64]范金辉,李仁兴,候旭,等.不同参数脉冲电流对不锈钢1Cr18Ni9Ti凝固组织的影响[J].铸造技术,2003,24：534-536
[65]范金辉,华勤,候旭,等.脉冲电流对奥氏体不锈钢凝固的影响[J].钢铁,2003,38：44-46
[66]王建中,王静松,常国威,等.电脉冲孕育处理对连铸Q235钢小方胚凝固组织的影响[J].辽宁工学院学报,1999,19：1-4
[67]Chang G W, Yuan J P, Wang Z D, et al. Effect of electric current on stability of solidification interface morphology [J]. Trans. Nonferrous Met. Soc. China,2000,10:445-448
[68]Coriell S R, McFadden G B, Wheeler A A, et al. The effect of an electric flied on the morphological stability of the crystal-melt interface of a binary alloy:Ⅱ Joule heating and thermoelectric effects [J]. J.Cryst. Growth,1989,94:334-346
[69]Mullins W W, Sakerka R F. Stability of planar interface during solidification of dilute binary alloy [J]. J. Applied Phys.,1964,35:444-451