Abstract: Al-Si alloy surface is remelting and solidification by electron beam to study the influence of electron beam scan technology on alloy properties. During the electron beam scanning the Al-Si alloy, the phenomenon of surface weightlessness which could affect the surface morphology of the parts and the distribution of the element would exist in the process. The effects of electron beam parameters such as scanning time, scanning frequency and power on the weightlessness of samples after remelting are discussed, theory on gasification differences is also analyzed, the formation conditions of splash is studied, the mechanism of weightlessness formation is disclosed. The experiment results show that weightlessness increases as time and power increase. High frequency block the process of weightlessness, the evaporation capacity of Si whose saturated vapor pressure is lower is more than Al. Under the condition of given parameters, the effective depth of sampling surface comes to 18.5 μm, the highest energy is appeared at 6 μm.The main reason of Al-Si alloy surface weightlessness are the splash of molten pool when the electron beam remelt Al-Si alloy surface and the evaporation of Al phase and Si phase.

Key words: Al-Si alloy, Electron beam, Splash, Weightlessness