中文摘要：

在原处，孔形成的观察被微焦点的 X 光检查成像使用在二 Al-Si 合金(7%Si 和 13%Si ) 的方向性的团结期间做。在两合金，小球形的毛孔开始远在 melt 形成离开最容易溶解稳固液体(S/L ) 连接然后在团结期间成长并且凝结。从团结的某毛孔罐头漂流和逃跑在相对高的速度融化前面。在团结的结束，留下的毛孔在近最容易溶解的合金维持球形的形态学，但是在 hypoeutectic 合金变得不规则。这被归因于在孔形成的二 alloys.The 机制之间的不同团结模式和铝树突相互作用简短在这份报纸被讨论。

英文摘要：

In-situ observation of porosity formation during directional solidification of two Al-Si alloys （7%Si and 13%Si） was made by using of micro-focus X-ray imaging.In both alloys,small spherical pores initially form in the melt far away from the eutectic solid-liquid （S/L） interface and then grow and coagulate during solidification.Some pores can float and escape from the solidifying melt front at a relatively high velocity.At the end of solidification,the remaining pores maintain spherical morphology in the near eutectic alloy but become irregular in the hypoeutectic alloy.This is attributed to different solidification modes and aluminum dendrite interactions between the two alloys.The mechanism of the porosity formation is briefly discussed in this paper.