| 摘要: |
| 利用磁场辅助制备的合金综合性能优异，广泛应用在工业生产、交通运输、航空航天等领域。不同磁场参数环境下合金硬度、耐磨性等服役性能有所差异，作用机理复杂多变。对新工艺驱动下不同磁场对金属凝固过程的作用规律进行总结， 弥补目前磁场辅助金属表面加工方法的研究短板，对金属表面工程发展有重大意义。归纳科研人员在不同磁场环境对金属表面加工的研究探索，分析对比金属材料在不同类型磁场环境下的晶核形核和生长过程差异，总结金属凝固过程在不同磁场下的变化规律，如晶界形貌改善、形核率提高、晶粒细化等。从晶粒微观形貌和合金宏观性能表现两方面出发，分析磁场作用下熔体内部传热传质变化，揭示稳恒磁场、脉冲磁场和交变磁场对金属凝固影响的作用机理，讨论不同参数的磁场对熔体作用效果差异，如磁场对熔池内部流动扰动、熔体内带电粒子受到的洛伦兹力等。综上，晶粒细化、合金性能提高是磁场作用下熔池传热传质变化和磁场作用力的综合体现。综合研究对比稳恒磁场、脉冲磁场和交变磁场对金属凝固的作用特点和作用机理，综述金属凝固领域当前热点问题，有助于统一磁场环境下金属凝固机理的争论，填补磁场环境下金属表面加工工艺的空白，对推进高性能金属表面制备研究有借鉴意义。 |
| 关键词: 金属工艺 表面工程 晶粒 微观形貌 宏观性能 磁场 |
| DOI：10.11933/j.issn.1007?9289.20220811002 |
| 分类号:TG244 |
| 基金项目:国家自然科学基金（52005511）；国家自然科学基金面上（52275227）资助项目 |
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| Review of the Effect of Different Magnetic Field on Metal Solidification |
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SONG Jiaxin1, GUO Weiling2, XING Zhiguo2, LI Zhixiong1, WANG Haidou3, ZHANG Lei4, HUANG Yanfei2
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1.College of Engineering, Ocean University of China, Qingdao 266100 , China;2.National Key Laboratory for Remanufacturing, Army Academy of Armored Forces, Beijing 100072 , China;3.National Engineering Research Center for Remanufacturing, Army Academy of Armored Forces,Beijing 100072 , China;4.School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300401 , China
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| Abstract: |
| Alloys prepared in a magnetic field environment have excellent comprehensive properties and are widely used in industrial production, transportation, aerospace, and other fields. The hardness, wear resistance, and other service properties of the alloy vary with the magnetic field parameters. Therefore, summarizing the mechanisms of different magnetic fields in the metal solidification process is of great significance for developing auxiliary metal technology. This paper summarizes the studies and exploration of metal surface processing by many researchers in different magnetic field environments. In addition, this study explores the rules of nucleation and growth of metal materials under the assistance of magnetic fields. According to the aspects of the microscopic morphology of the grains and the macroscopic properties of the alloy, the changes in heat and mass transmission, crystal boundary shape variation, increase in nucleation rate, and grain size refinement are analyzed, and the effects of the steady, pulsed, and alternating magnetic fields on metal solidification are revealed. The various influences of different magnetic fields are discussed in this paper, such as magnetic induction, intensity produced by the magnetic field, and charged particles within the melt by the Lorentz force. In the process of metal solidification assisted by a steady magnetic field, both the thermoelectric force generated by the thermoelectric current and magnetic field and the electromagnetic brake force generated by the natural flow of the melt jointly affects the dendrite growth and internal flow of the melt, which is essentially the Lorentz force under the action of a magnetic field. Furthermore, the magnetic induction intensity is the most crucial factor affecting the electromagnetic brake and thermoelectric forces. The combined effect on the melt first increases and then decreases with increasing magnetic induction intensity. Pulsed magnetic fields are essential in improving the magnetism, corrosion resistance, and electrochemical performance of molten metals through wall ionization, electromagnetic oscillation, and the Joule thermal effect. The various effects of the magnetic field are concentrated in the internal flow enhancement and temperature gradient reduction of the molten pool. Electromagnetic stirring and forced convection promote dendrite breaking and grain refinement under an alternating magnetic field. Furthermore, the phase distribution is more uniform and inhibits compositional segregation. The application of metal solidification in a magnetic field environment focuses on emerging surface processing technologies such as deposition and cladding from traditional alloy manufacturing processes such as casting and welding. The exploration of new processes in a magnetic field environment, such as magnetic-field-assisted coating solidification, is also the future development direction of this field. The research method has changed from a simple performance enhancement effect test to a theoretical model calculation. In conclusion, grain refinement and alloy performance improvement are comprehensive embodiments of heat and mass transmission and the magnetic force in the molten pool under the action of a magnetic field. The mechanism of action of the metal solidification process under different magnetic fields gradually tends to be consistent. Refining and quantifying the various effects of different magnetic fields on the alloy solidification structure, unifying grain change processes and mechanisms, and other studies still require scholars' unremitting efforts. A comprehensive study and comparison of the steady, pulsed, and alternating magnetic fields on metal solidification characteristics and mechanisms are summarized, which helps unify the debate on the metal solidification mechanism in a magnetic field environment, fills in the gaps in metal surface processing technology in a magnetic field environment, and has reference significance for promoting research on high-performance metal surface preparation. |
| Key words: metal craft surface engineering crystalline grain microscopic morphology macroscopic performance magnetic field |
