Mg-Zn-Al三元系富镁角350℃等温截面  

Isothermal section of Mg-rich corner at 350℃ in Mg-Zn-Al ternary system

作　　者：任玉平[1] 李俊杰[1] 李松[1] 肖娜[1] 孙世能[1] 秦高梧[1] 

机构地区：[1]东北大学材料各向异性与织构教育部重点实验室,沈阳110819

出　　处：《中国有色金属学报》2013年第2期297-302,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(50901017;51171043);国家"十二五"科技支撑计划资助项目(2011BAE22B04-2);教育部新教师项目(20090042120008);中央校基本科研业务费资助项目(N100702001;N110410006)

摘　　要：采用合金法,利用X射线衍射、扫描电镜及能谱成分分析等手段测定Mg-Zn-Al合金350℃时的相平衡关系及其成分,建立富镁角350℃等温截面。结果表明:α-Mg固溶体与L、φ、γ三相保持相平衡关系,不存在以前普遍认为的τ与α-Mg的相平衡。获得350℃时φ相成分范围,即53.5%～57.2%Mg、17.7%～30.7%Zn和15.8%～27.7%Al(摩尔分数)。Zn和Al两种元素可以同时固溶于α-Mg相中。但Al的加入提高了Zn在α-Mg中的溶解度,当α-Mg和L相平衡时,溶解度最大可达3.9%,远大于Mg-Zn二元系的2.1%。而当α-Mg与γ相平衡时,Zn的加入降低Al在α-Mg中的溶解度,即由Mg-Al二元系的7.8%降至5.2%。Al在Mg-Zn二元金属间化合物中的固溶度较大,可达7.7%,从而使其热稳定性得到提高。The phase equilibria and their compositions in the Mg-rich corner of Mg-Zn-Al ternary system at 350℃ were determined through the equilibrated alloy method by X-ray diffractometry （XRD） and scanning electron microscopy （SEM） assisted with energy dispersive spectroscopy （EDS）, and thus the isothermal section of the Mg-rich corner at 350℃ in the ternary system was constructed. There are three phases at this temperature in equilibrium with a-Mg solid solution, including the liquid, φ and ？ phases, while not the z ternary intermetallic compound as previously accepted. Moreover, the composition ranges of the φ intermetallic compound, i.e., 53.5%-57.2%Mg, 17.7%-30.7%Zn and 15.8%-27.7%Al （mole fraction）, are also obtained. The zinc and aluminum are simultaneously soluble in the a-Mg phase The solubility of Zn in the a-Mg phase increases due to the addition of Al, and the maximum solubility is 3.0%Zn, more than that of Mg-Zn binary system （2.1%Zn） when the a-Mg solid solution is in equilibrium with the liquid phase. However, the solubility of Al in the a-Mg phase decreases due to the addition of Zn when the a-Mg phase is in equilibrium with the y intermetallic compound, i.e., the Al solubility is 7.8% in the Mg-Al binary system, decreasing to 5.2%. At the same time, the solubility of the Al in the Mg-Zn intermetallic compound is improved to 7.7%.

关 键 词：Mg-Zn-Al三元系 相平衡 平衡合金法 固溶度 

分 类 号：TG111[金属学及工艺—物理冶金]