Jianbo YU
,
Zhongming REN
金属学报(英文版)
doi:10.1016/S1006-7191(08)60068-X
The effects of electromagnetic vibration on the grain refinement in directional solidification were investigated. It was found that the electromagnetic vibration applied in the melt not only can refine grains remarkably but also can enhance both tensile strength and ductility values of Al-6%Si alloy. SEM graphs show that coarse dendrite structure was broken up into a somewhat globular structure, and the morphology of eutectic silicon was changed from flaky to fibrous under electromagnetic vibration treatment. The refine mechanism under electromagnetic vibration was discussed.
关键词:
Electromagnetic vibration
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Jianbo YU
,
Zhongming REN
,
Weili REN
,
Kang DENG
,
Yunbo ZHONG
金属学报(英文版)
doi:10.1016/S1006-7191(08)60088-5
An electromagnetic vibration was generated by simultaneously imposing a strong static magnetic field (up to 10 T) and an alternative electricity current to the metal. Its effects on the solidification structure of eutectic Al-Si alloy have been investigated experimentally. It is found that the eutectic structure has been refined by solely imposing high magnetic field while it is coarsened under the electromagnetic vibration. Furthermore, polyhedral Si grains and non-dendritic α-Al appeared when the electromagnetic vibration strength was strong enough. The refining of eutectic structure is attributed to the decrease of diffusion coefficient caused by the strong magnetic field. The coarseness of eutectic structure may be attributed to the convection caused by electromagnetic vibration. Strong convection may break co-operative growth of eutectic phases to form polyhedral Si grains and non-dendritic α-Al.
关键词:
Strong magnetic field
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