Effects of calcium addition and electromagnetic stirring on the microstructure of AZ91 magnesium alloy and refinement mechanism were investigated. The results show that calcium addition ranging from 0.1 wt% to 0.3 wt% does not lead to formation of any new phases but cause the refinement of as-cast microstructure.However, combined calcium alloying and electromagnetic stirring significantly decrease the grain size, change the morphologies of the β-Mg17Al12 phases,and reduce their volume percentage. The minimum grain size of AZ91 alloy is obtained in the ease of the addition of 0.2 wt% Ca withexciting voltage of 100 V. The microstructural refinement is attributed to the increase of the degree of undereooling and nucleation temperature of primary α-Mg phases on the basis of DTA analysis results.
参考文献
| [1] | Polmear I J.Magnesium Alloys and Applications[J].Materials Science and Technology,1994(01):1-16. |
| [2] | DAVID H. StJOHN;MA QIAN;MARK A. EASTON .Grain Refinement of Magnesium Alloys[J].Metallurgical and Materials Transactions, A. Physical Metallurgy and Materials Science,2005(7):1669-1679. |
| [3] | Bamberger M. .Structural refinement of cast magnesium alloys [Review][J].Materials Science and Technology: MST: A publication of the Institute of Metals,2001(1):15-24. |
| [4] | Kinji Hirai;Hidetoshi Somekawa;Yorinobu Takigawa .Effects of Ca and Sr addition on mechanical properties of a cast AZ91 magnesium alloy at room and elevated temperature[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2005(1/2):276-280. |
| [5] | LIU Shengfa,KANG Liugen,HAN Hui,WANG Zhongfan.The Role of Calcium in Microstructural Refinement of AZ91 Magnesium Alloy[J].武汉理工大学学报(材料科学版)英,2006(04):45-47. |
| [6] | L. L. Rokhlin;N. I. Nikitina .EFFECT OF CALCIUM ON THE PROPERTIES OF THE Mg - Al SYSTEM[J].Metal Science and Heat Treatment,2003(5/6):171-173. |
| [7] | Easton Mark;StJohn David .Grain Refinement of Aluminum Alloys[J].Metallurgical and Materials Transactions A:Physical Metallurgy and Materials Science,1999,30A(06):1613-1633. |
| [8] | Peijie Li;Bin Tang;E.G. Kandalova .Microstructure and properties of AZ91D alloy with Ca additions[J].Materials Letters,2005(6):671-675. |
| [9] | B.I. Jung;C.H. Jung;T.K. Han .Electromagnetic stirring and Sr modification in A356 alloy[J].Journal of Materials Processing Technology,2001(1/3):69-73. |
| [10] | LIU Sheng-fa,KANG Liu-gen,HAN Hui,LIU Lin-yan,ZOU Xiao-qiang,GUO Hong-he.Influence of electromagnetic stirring on microstructure of AZ91-0.8%Ce magnesium alloy[J].中南工业大学学报（英文版）,2006(06):613-617. |
| [11] | Hu H Q.Principle of Solidification[M].北京:机械工业出版社,1991:124. |
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