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pISSN : 1598-706X / eISSN : 2288-8381


한국주조공학회지 (23권1호 40-46)

Effect of the Casting Conditions on the Globulization of Primary Al of AlSi_7 Mg Alloy

AlSi_7 Mg 알루미늄 합금의 초정 구형화에 대한 주조조건의 영향

Yo-Sub Han, Ho-In Lee, Jae-Chul Lee

Korea Institue of Science and Technology


Semisolid forming requires alloys with non-dendritic microstructure of the thixotropy. Recently, low pouring temperture method without stirring, i.e. liquidus casting has been found out new fabrication method of the semisolid metals. Effects of melt superheat and mold conditions on the globulization of primary Al of AlSi_7 Mg alloy were investigated in gravity casting process without stirring. The microstructures of primary Al as function of melt superheat and mold temperature show globular, rosette and dendritic shapes. The conditions for globular microstructure of primary Al were low melt superheat < 35 K and low mold temperature < 500 K. The thermal conditions for globular microstructure of primary Al were undercooled melt at early solidification stages and slow cooling < 0.6 K/s. It was found that the initial microstructure was maintained throughout the solidification and the globules of primary Al can be obtained by high nucleation of fine and spherical nuclei due to enhanced undercooling of melt.


Semi-solid forming, Globulization of primary Al, AlSi_7 Mg alloy, Casting condition