Mg_(70)Zn_(28)Y_2合金凝固过程、凝固组织及包晶反应初生相研究  

Study on Solidification Process, Microstructures and the Primary Phase of Peritectic Reaction of Mg_(70)Zn_(28)Y_2 Alloy

作　　者：万迪庆[1] 杨根仓[1] 朱满[1] 程素玲[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

出　　处：《稀有金属材料与工程》2007年第10期1732-1735,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50571081);航空基金(04G53024)

摘　　要：采用XRD,SEM,EDX,TEM,DTA等试验分析手段及快淬方法对Mg70Zn28Y2准晶合金凝固过程、凝固组织以及对和准晶形成相关的包晶反应初生相进行了研究。Mg70Zn28Y2合金铸态组织由α-Mg枝晶,Mg7Zn3基体相和二十面体准晶相组成。在铸态Mg-Zn-Y合金中观察到了完美的呈5次旋转对称性的平衡态准晶晶体外形。Mg70Zn28Y2合金凝固过程中准晶由包晶反应生成。差热分析显示包晶反应初生相在563℃形成,准晶形成的温度为416℃。能谱分析结果显示包晶反应初生相的成分为Mg22.94Zn55.73Y21.33。通过快淬方法保留的包晶反应初生相呈现粗大枝晶状。然而,通过背散射图片中所观察到准晶中的残留包晶初生相尺寸较小。Adopting XRD, SEM, EDX, TEM, DTA and quenching techniques, an investigation on the solidification of Mg70Zn28Y2 quasicrystal alloy was carried out. The microstructure of as-solidified Mg70Zn28Y2 alloy consists of α-Mg dendrite, Mg7Zn3 phase and petal-like icosahedral quasicrystal phase. The equilibrium shape of quasicrystal in as-solidified Mg70Zn28Y2 alloy is of icosahedron. The peritectic reaction occurs in Mg70Zn28Y2 alloy solidification sequence, in which DTA analysis shows that the primary phase of peritectic reaction forms at 563℃ and then icosahedral quasicrystal phase forms at 416 ℃. EDX analysis shows that the approXimation composition of the primary phase precipitated before peritectic reaction is Mg22.94Zn 55.73Y21.33. The primary phase of pedtectic reaction remained through quench process shows coarse dendrite shape, but its size is relatively small according to BSD image.

关 键 词：Mg—Zn—Y准晶合金 二十面体准晶相 初生相 二十面体准晶外形 

分 类 号：TG111.4[金属学及工艺—物理冶金]