SOLIDIFICATION PROCESS OF α(Al)-Mg_2Ge PSEUDOBINARY EUTECTIC ALLOYS

ＳＯＬＩＤＩＦＩＣＡＴＩＯＮＰＲＯＣＥＳＳＯＦα（Ａｌ）Ｍｇ２ＧｅＰＳＥＵＤＯＢＩＮＡＲＹＥＵＴＥＣＴＩＣＡＬＬＯＹＳ①ＺｈａｏＳｈｅｎｇｘｕ，ＬｉＳｈｕｎｐｕ，ＺｈａｏＤｅｑｉａｎ，ＰａｎＭｉｎｇｘｉａｎｇａｎｄＣｈｅｎＸｉｃｈｅｎＩｎｓｔｉｔｕ...

Solidification process of α(Al)Mg_2Ge pseudobinary eutectic alloys in Al-Mg-Ge system has been studied by directional solidification and electron microscopy techniques. It was demonstrated that the morphology of the primary crystal of phase Mg_2Ge is octahedron enclosed with {111} planes and Mg_2Ge is the favored nucleating phase during eutectic solidification of this alloy. The branching process during solidification fits the mechanism of branching in the preferred growth direction. First, the primary branching occurs in the [110] direction of the primary crystal of Mg_2Ge, and then the second branching appears in the direction of the primary branch. It progresses in this way till stable growth.