METALS AND METAL MATRIX COMPOSITES |
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Morphology Evolution Mechanism of α-Al Dendrite of Hypoeutectic Al-7%Si Alloy Regulated by Low Voltage Alternating Current Pulse |
LI Ning 1, ZHANG Limin1, XING Hui1, ZHANG Rong1, YIN Pengfei2, WU Yaoyan1, WANG Juan1, LIU Hainan1
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1 Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi’an 710072; 2 College of Science, Sichuan Agricultural University, Ya’an 625014 |
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Abstract The α-Al dendrite morphology evolution law of hypoeutectic Al-7% Si alloy under low voltage alternating current pulse (LACP) has been investigated in this paper. The distribution of current pulse and electromagnetic force in the alloy melt were numerically simulated. LACP of different current density was imposed in whole solidification process of the alloy and the wire metal tube was embedded in sand mould to restrain the melt convection. The mechanism of microstructure regulated by LACP was analyzed. The results show that the degree of refining of α-Al dendrite was aggravated with the increase of current pulse density in cas-ting samples of without wire metal tube and outside of wire metal tube and inside of wire metal tube. However, some of α-Al dendrites turn into rosiness from dendritic is related to the current density of LACP and location. There were significant differences in the morphology of the α-Al dendrite between casting samples of without wire metal tube and outside of wire metal tube and inside of wire metal tube. The analysis suggests that the change of α-Al dendrite was caused by melt convection resulted from the pulse electromagnetic force. The α-Al morphology can be predicted through calculating the Reynolds number of alloy melt, after Al-7% Si alloy was treated with different current density LACP.
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Published: 21 December 2018
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1 Conrad H. Influence of an electric or magnetic field on the liquid-so-lid transformation in materials and on the microstructure of the solid [J]. Materials Science and Engineering: A,2000,287(2):205. 2 Li X, Ren Z M, Fautrelle Y. Phase distribution and phase structure control through a high gradient magnetic field during the solidification process [J]. Materials and Design,2008,29(9):1796. 3 Zhai W, Liu H M, Zuo P F, et al. Liquid phase separation and monotectic structure evolution of ternary Al62.6Sn28.5Cu8.9 immiscible alloy within ultrasonic field [J]. Materials Letters,2015,141:221. 4 Zuo P F, Wang H P, Yang S J, et al. Anomalous temperature dependence of liquid state density for Ni50Ti50 alloy investigated under electrostatic levitation state [J]. Chemical Physics Letters,2017,681(1):101. 5 Masayuki N, Yuh S, MertOn C F. Modification of solidification structures by pulse electric discharging [J]. ISIJ International,1990,30:27. 6 Barnak J P, Sprecher A F, Conrad H. Colony (grain) size reduction in eutectic Pb-Sn castings by electropulsing [J]. Scripta Metallurgica Et Materialia,1995,32(6):879. 7 He S X, Wang J, Sun B D, et al. Effect of high density pulse current on solidification structure of A356 alloy [J]. The Chinese Journal of Nonferrous Metals,2002,12(3):426(in Chinese). 何树先,王俊,孙宝德,等.高密度脉冲电流对A356铝合金凝固组织的影响[J].中国有色金属学报,2002,12(3):426. 8 Xiao Y H, Gao M, Yang F, et al. Influence of electropulsing time on solidification structure and property of the casting ZA12 alloy [J]. Hot Working Technology,2004,27(1):38(in Chinese). 肖蕴华,高明,杨菲,等.电脉冲时间对铸造ZA12合金凝固组织和性能的影响[J].热加工工艺,2004,27(1):38. 9 Ban C Y, Yi H, Ba Q X, et al. Influence of pulse electric current on solidification structures of Al-Si alloys [J]. Materials Science Forum,2007,546-549:723. 10 Zhang Y H, Song C J, Zhu L, et al. Influence of electric current pulse treatment on the formation of regular eutectic morphology in an Al-Si eutectic alloy [J]. Metallurgical and Materials Transactions B,2011,42(3):604. 11 Liao X L, Zhai Q J, Luo J, et al. Refining mechanism of the electric current pulse on the solidification structure of pure aluminum [J]. Acta Materialia,2007,55(9):3103. 12 Ma J H, Li J, Gao Y L, et al. Grain refinement of pure Al with different electric current pulse modes [J]. Materials Letters,2009,63(1):142. 13 Li X B, Lu F G, Cui H C, et al. Effect of electric current pulse on flow behaviour of Al melt in parallel electrode process [J]. Materials Science and Technology,2013,29(2):226. 14 Rahnama A, Qin R S. Electropulse-induced microstructural evolution in a ferritic-pearlitic 0.14% C steel [J]. Scripta Materialia,2015,96:17. 15 Zhou Y Z, Qin R S, Xiao S H. Reversing effect of electropulsing on damage of 1045 steel [J]. Journal of Materials Research,2000,15(5):1056. 16 Zhang L M, Liu H N, Li N, et al. The relevance of forced melt flow to grain refinement in pure aluminum under a low-frequency alternating current pulse [J]. Journal of Materials Research,2016; 31(3):396. 17 Li N, Zhang R, Zhang L M, et al. Study on grain refinement mec-hanism of hypoeutectic Al-7% Si alloy under low voltage alternating current pulse [J]. Acta Metallurgica Sinica,2017,53(2):192(in Chinese). 李宁,张蓉,张利民,等.低压交流电脉冲下Al-7%Si合金晶粒细化机理研究[J].金属学报,2017,53(2):192. 18 Zhang L M, Zhang R, Chen W J, et al. Effect of a novel low-voltage alternating current pulse on solidification structure of Al-7Si-0.52Mg alloy [J]. Advanced Materials Research,2012,482-484(3):1431. 19 Brandt R, Neuer G. Electrical resistivity and thermal conductivity of pure aluminum and aluminum alloys up to and above the melting temperature [J]. International Journal of Thermophysics,2007,28(5):1429. 20 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 Materialia,2007,55(11):3803. 21 Sklyarchuk V, Plevachuk Y, Yakymovych A, et al. Structure sensitive properties of liquid Al-Si alloys [J]. International Journal of Thermophysics,2009,30(4):1400. 22 Zuo Y B, Nagaumi H, Cui J Z. Study on the sump and temperature field during low frequency electromagnetic casting a superhigh strength Al-Zn-Mg-Cu alloy [J]. Journal of Materials Processing Technology,2008,197(1):109. 23 Liu Z, Mao W M, Zhao Z D. Effect of grain refining on primary α phase in semi-solid A356 alloy prepared by low superheat pouring and slight electromagnetic stirring [J]. Acta Metallurgica Sinica-English Letters,2008,21(1):57. 24 Metan V, Eigenfeld K, Räbiger D, et al. Grain size control in Al-Si alloys by grain refinement and electromagnetic stirring [J]. Journal of Alloys and Compounds,2009,487(1):163. 25 Dirk Räbiger, Zhang Y H, Vladimir Galindo, et al. The relevance of melt convection to grain refinement in Al-Si alloys solidified under the impact of electric currents [J]. Acta Materialia,2014,79:327. 26 Di X J, Deng S J, Wang B S. Effect of pulse current on mechanical properties and dendritic morphology of modified medium manganese steel welds metal [J]. Materials and Design,2015,66:169. 27 Xu Y, Wang E G, Li Z, et al. Effects of vertical electromagnetic stirring on grain refinement and macrosegregation control of bearing steel billet in continuous casting [J]. Journal of Iron and Steel Research,2017,24(5):483. 28 Zhang J K, Li Y. Effects of different rotation speeds on microstructure, hardness and corrosion resistance of the Au-Cu alloy [J]. Gold Bull,2017,50(2):137. 29 Tang P, Li W F, Zhao Y J, et al. Influence of strontium and lanthanum simultaneous addition on microstructure and mechanical properties of the secondary Al-Si-Cu-Fe alloy [J]. Journal of Rare Earths,2017,37(5):485. |
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