Mg30Zn60Y10合金中二十面体准晶相的形成和生长  

Formation and Growth of Icosahedral Quasicrystal in Mg30Zn60Y10 Alloy

作　　者：万迪庆[1] 杨根仓[1] 刘雅娟[2] 朱满[1] 周尧和[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]南昌理工学院,江西南昌330013

出　　处：《铸造》2006年第1期9-11,共3页Foundry

摘　　要：通过常规凝固方法在Mg30Zn60Y10三元合金中获得大体积分数准晶。准晶相由包晶反应生成。能谱分析结果表明包晶反应中初生相的成分近似为Mg16.32Zn70.60Y13.08,准晶相成分为Mg36.94Zn56.21Y6.63。差热分析显示初生相在723℃形成,准晶相生成温度为648℃。利用快淬方法使准晶相生长初期形貌得以保留,发现准晶相初期形貌受初生相形貌直接影响,但随后则按其晶体学优先方向生长,最终长成花瓣状准晶。准晶合金凝固过程中生成的低温相越多,准晶相熟化时间越长,越容易使准晶花瓣端部粗化以及在端部发生分叉。端部的分叉使得花瓣准晶破碎,这些破碎的准晶游离到低温相中在界面能的作用下形成多边形结构。A large fractional icosahedral quasicrystal is gained in Mg30Zn60Y10 ternary alloy. The peritectic reaction occurs in the icosahedral quasicrystal formation. EDX analysis shows that the approximation composition of the primary phase precipitated before peritectic reaction and icosahedral quasicrystal phase are Mg16.32Zn70.60Y13.08 and Mg36.94Zn56.21Y6.63 respectively. DSC analysis shows that in solidification process of the alloy the primary phase first crystals at 723℃ and then icosahedral quasicrystal forms at 648℃. The primary morphology of icosahedral quasicrystal is obtained by quenching alloy melt on iron plate. The quench results indicate that the primary morphology of icosahedral quasicrystal has greatly relation to pattern of primary phase and then the quasicrystal grows in its preferential crystal direction. In the solidification process, the more content of low-temperature phases （Mg7Zn3）, and the longer curing time, the more easily making the end of the petal-like icosahedral quasicrystalcoarsed and branched. Laterly the branched quaicrystal fractures and floats to the low-temperature phases of liquid and then forms the polygonal quaicrystal by the action of interface enerav.

关 键 词：MG-ZN-Y合金 二十面体准晶相 形貌特征 凝固 

分 类 号：TG111[金属学及工艺—物理冶金]