横向静磁场对激光熔化增材制造Al-12%Si合金凝固组织的影响
作者简介 帅三三,男,1988年生,博士
收稿日期: 2017-07-21
网络出版日期: 2017-11-02
基金资助
国家自然科学基金项目Nos.51690162和51604171,中国博士后基金项目Nos.2017T100291和2017M611530,以及西北工业大学凝固技术国家重点实验室开放课题项目Nos.SKLSP201706和SKLSP201602
Effect of Transverse Static Magnetic Field on Microstructure of Al-12%Si Alloys Fabricated by Powder-BlowAdditive Manufacturing
Received date: 2017-07-21
Online published: 2017-11-02
Supported by
Supported by National Natural Science Foundation of China (Nos.51690162 and 51604171), China Postdoctoral Science Foundation (Nos.2017T100291 and 2017M611530) and Fund of the State Key Laboratory of Solidification Processing in NWPU (Nos.SKLSP201706 and SKLSP201602)
利用送粉式激光熔化3D打印工艺,研究了外加横向稳恒磁场对3D打印Al-12%Si合金构件凝固组织的影响。结果表明,在有/无横向稳恒磁场下,激光熔化单道薄壁试样的宏观凝固组织未发生明显改变,其主要以白亮带(以α-Al相为主)和灰暗区(以Al-Si共晶相为主)为基本单元叠加构成。而微观组织分析表明,无磁场时灰暗区内的初生α-Al相呈柱状枝晶形态,施加了0.35 T横向稳恒磁场后,试样灰暗区内的初生α-Al相全部转变为等轴枝晶形态,且枝晶臂发达。基于热电磁力及其Hartman无量纲数(用于表征稳恒磁场对金属熔体流动抑制作用的参数)估算分析表明,0.35 T稳恒磁场下,作用于初生α-Al枝晶上的热电磁力可达105 N/m3量级;Hartman数远大于10,表明激光熔化微小金属熔池中强烈的Marigoni以及热溶质对流一定程度上被抑制。分析认为,稳恒磁场下凝固组织灰暗区内α-Al相柱状枝晶向等轴枝晶的转变是固相中热电磁力(约105 N/m3)对枝晶的破碎作用导致,而等轴枝晶发达的枝晶臂则是横向稳恒磁场抑制熔体流动的结果。
关键词： 增材制造; 横向静磁场; Al-12%Si合金; CET转变; 热电磁力
帅三三 , 林鑫 , 肖武泉 , 余建波 , 王江 , 任忠鸣 . 横向静磁场对激光熔化增材制造Al-12%Si合金凝固组织的影响[J]. 金属学报, 2018 , 54(6) : 918 -926 . DOI: 10.11900/0412.1961.2017.00305
Due to the great advantage in manufacturing component with complex structures, additive manufacturing (3D print), essentially the rapid solidification of tiny metallic molten pool (hemisphere like with diameter ranging from dozens of microns to several millimeters) has become an important formation technique. Using powder laser melting, the effect of transverse static magnetic field on the solidified structure of additive manufactured Al-12%Si alloy was studied. The macrostructure was formed by white band (mainly primary α-Al phase) and dark grey area (mainly eutectic phase) and no obvious influence was presented with or without static transverse magnetic field of 0.35 T. However, for the microstructure, the primary α-Al in dark grey area formed as columnar structure without magnetic field was found to transform to dendritic like with developed dendrite arms when under a static transverse magnetic field. The analysis on thermoelectricity and dimensionless Hartman parameter which used to characterize the restriction of static magnetic field on molten flows show that under a static transverse magnetic field of 0.35 T, the thermoelectric magnetic force can be as high as a magnitude of 105 N/m3, and Hartman values is far more than 10. The results indicate that the Marigoni and thermosolutal convection in laser melting pool was restricted. The transform from columnar to equiaxed dendrite of primary α-Al in dark grey area under static magnetic field was attributed to the fragmentation by thermoelectric magnetic force (105 N/m3) in solid phase. In addition, the formation of high order dendrite arms was supposed to be caused by the restriction of static magnetic field on the melt.
| [1] | Yang S, Huang W D, Liu W J, et al.Research on laser rapid directional solidification with ultra-high temperature gradient[J]. Chin. J. Lasers, 2002, 29: 475(杨森, 黄卫东, 刘文今等. 激光超高温度梯度快速定向凝固研究[J]. 中国激光, 2002, 29: 475) |
| [2] | Kruth J P, Levy G, Klocke F, et al.Consolidation phenomena in laser and powder-bed based layered manufacturing[J]. CIRP Ann., 2007, 56: 730 |
| [3] | Kobryn P A, Semiatin S L.The laser additive manufacture of Ti-6Al-4V[J]. JOM, 2001, 53(9): 40 |
| [4] | Wang X Y, Chen J, Lin X, et al.Microstructures of laser forming repair 7050 aluminum alloy with AlSi12 powder[J]. Chin. J. Lasers, 2009, 36: 1585(王小艳, 陈静, 林鑫等. AlSi12粉激光成形修复7050铝合金组织[J]. 中国激光, 2009, 36: 1585) |
| [5] | Siddique S, Imran M, Wycisk E, et al.Influence of process-induced microstructure and imperfections on mechanical properties of AlSi12 processed by selective laser melting[J]. J. Mater. Process. Technol., 2015, 221: 205 |
| [6] | Song M H, Lin X, Yang G L, et al.Influence of forming atmosphere on the deposition characteristics of 2Cr13 stainless steel during laser solid forming[J]. J. Mater. Process. Technol., 2014, 214: 701 |
| [7] | Liu F C, Lin X, Huang C P, et al.The effect of laser scanning path on microstructures and mechanical properties of laser solid formed nickel-base superalloy Inconel 718[J]. J. Alloys Compd., 2011, 509: 4505 |
| [8] | Goetz A, Hasler M F.The thermoanalysis of metal single crystals and a new thermoelectric effect of bismuth crystals grown in magnetic fields[J]. Phys. Rev., 1930, 36: 1752 |
| [9] | Savitsky E M, Torchinova R S, Turanov S A.Effect of crystallization in magnetic field on the structure and magnetic properties of Bi-Mn alloys[J]. J. Cryst. Growth, 1981, 52: 519 |
| [10] | Farrell D E, Chandrasekhar B S, De Guire M R, et al.Superconducting properties of aligned crystalline grains of Y1Ba2Cu3O7-δ[J]. Phys. Rev., 1987, 36B: 4025 |
| [11] | Sassa K, Morikawa H, Asai S.Controls of precipitating phase alignment and crystal orientation using high magnetic field[J]. J. Jpn Inst. Met. Mater., 1997, 61: 1283(佐々 健介, 森川拓, 浅井滋生. 強磁場による晶出相の配向と結晶方位の制御[J]. 日本金属学会誌, 1997, 61: 1283) |
| [12] | Tiller W A, Jackson K A, Rutter J W, et al.The redistribution of solute atoms during the solidification of metals[J]. Acta Metall., 1953, 1: 428 |
| [13] | Li X, Gagnoud A, Fautrelle Y, et al.Dendrite fragmentation and columnar-to-equiaxed transition during directional solidification at lower growth speed under a strong magnetic field[J]. Acta Mater., 2012, 60: 3321 |
| [14] | Li X, Fautrelle Y, Zaidat K, et al.Columnar-to-equiaxed transitions in Al-based alloys during directional solidification under a high magnetic field[J]. J. Cryst. Growth, 2010, 312: 267 |
| [15] | Utech H P, Flemings M C.Elimination of solute banding in indium antimonide crystals by growth in a magnetic field[J]. J. Appl. Phys., 1966, 37: 2021 |
| [16] | Oreper G M, Szekely J.The effect of an externally imposed magnetic field on buoyancy driven flow in a rectangular cavity[J]. J. Cryst. Growth, 1983, 64: 505 |
| [17] | Witt A F, Herman C J, Gatos H C.Czochralski-type crystal growth in transverse magnetic fields[J]. J. Mater. Sci., 1970, 5: 822 |
| [18] | Lehmann P, Moreau R, Camel D, et al.Modification of interdendritic convection in directional solidification by a uniform magnetic field[J]. Acta Mater., 1998, 46: 4067 |
| [19] | Tewari S N, Shah R, Song H.Effect of magnetic field on the microstructure and macrosegregation in directionally solidified Pb-Sn alloys[J]. Metall. Mater. Trans., 1994, 25A: 1535 |
| [20] | Moreau R, Laskar O, Tanaka M, et al.Thermoelectric magnetohydrodynamic effects on solidification of metallic alloys in the dendritic regime[J]. Mater. Sci. Eng., 1993, A173: 93 |
| [21] | Li X, Fautrelle Y, Ren Z M.Influence of thermoelectric effects on the solid-liquid interface shape and cellular morphology in the mushy zone during the directional solidification of Al-Cu alloys under a magnetic field[J]. Acta Mater., 2007, 55: 3803 |
| [22] | Xuan W D, Ren Z M, Li C J.Effect of a high magnetic field on microstructures of Ni-based superalloy during directional solidification[J]. J. Alloys Compd., 2015, 620: 10 |
| [23] | Wang J, Fautrelle Y, Ren Z M, et al.Thermoelectric magnetic force acting on the solid during directional solidification under a static magnetic field[J]. Appl. Phys. Lett., 2012, 101: 251904 |
| [24] | Mikelson A E, Karklin Y K.Control of crystallization processes by means of magnetic fields[J]. J. Cryst. Growth, 1981, 52: 524 |
| [25] | Wang C J, Dong M, Liu T, et al.Effects of high magnetic fields on the distribution of primary α-Al dendrites of Al-7%Si alloys during solidification[J]. Mater. Rev., 2016, 30(2): 90(王长久, 董蒙, 刘铁等. 强磁场对Al-7%Si合金凝固过程中初生α-Al枝晶分布的影响[J]. 材料导报, 2016, 30(2): 90) |
| [26] | Li X, Gagnoud A, Ren Z M, et al.Investigation of thermoelectric magnetic convection and its effect on solidification structure during directional solidification under a low axial magnetic field[J]. Acta Mater., 2009, 57: 2180 |
| [27] | Yu X B.Microstructure and mechanical properties of GH4169 superalloy fabricated by electromagnetic stirring assisted laser solid forming [D]. Nanchang: Nanchang Aeronautical University, 2015(余小斌. 电磁搅拌激光立体成形GH4169合金的组织和力学性能研究 [D]. 南昌: 南昌航空大学, 2015) |
| [28] | Wang W, Cai L, Yang G, et al.Research on the coaxial powder feeding nozzle for laser cladding[J]. Chin. J. Lasers, 2012, 39: 0403003(王维, 才磊, 杨光等. 激光熔覆同轴送粉喷嘴研制[J]. 中国激光, 2012, 39: 0403003) |
| [29] | Dinda G P, Dasgupta A K, Bhattacharya S, et al.Microstructural characterization of laser-deposited Al 4047 alloy[J]. Metall. Mater. Trans., 2013, 44A: 2233 |
| [30] | Dinda G P, Dasgupta A K, Mazumder J.Evolution of microstructure in laser deposited Al-11.28%Si alloy[J]. Surf. Coat. Technol., 2012, 206: 2152 |
| [31] | Khine Y Y, Walker J S.Thermoelectric magnetohydrodynamic effects during bridgman semiconductor crystal growth with a uniform axial magnetic field[J]. J Cryst. Growth, 1998, 183: 150 |
| [32] | Willers B, Eckert S, Nikrityuk P A, et al.Efficient melt stirring using pulse sequences of a rotating magnetic field: Part II. Application to solidification of Al-Si alloys[J]. Metall. Mater. Trans., 2008, 39B: 304 |
| [33] | Wu C Y.Effect of strong magnetic field on the microstructure and properties of materials [D]. Dalian: Dalian University of Technology, 2003(吴存有. 强磁场作用力对材料组织和性能的影响 [D]. 大连: 大连理工大学, 2003) |
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