GPa级超高压下Mg-6Zn-1Y合金凝固过程及准晶形成  

Solidification Process and Formation of Quasi-crystal Phase in Mg-6Zn-1Y Alloy under Pressure in the Order of GPa

作　　者：董允[1] 林小娉[1] 徐瑞[2] 刘士俊[1] 田莎莎[1] 

机构地区：[1]东北大学秦皇岛分校,河北秦皇岛066004 [2]燕山大学,河北秦皇岛066004

出　　处：《稀有金属材料与工程》2014年第5期1117-1122,共6页Rare Metal Materials and Engineering

基　　金：辽宁省自然科学基金(301112063);河北省自然科学基金(E2010001398)

摘　　要：采用FactSage热力学软件和镁基数据库计算了Mg-6Zn-1Y合金的凝固路径。利用SEM并配合EDS,XRD,DSC研究了超高压下Mg-6Zn-1Y合金的凝固过程和准晶形成。结果表明:常压下该合金凝固组织主要由粗大α-Mg枝晶和分布在枝晶间含准晶I-Mg3YZn6相的层片状组织等组成,合金凝固过程的实验分析与热力学计算结果吻合较好。Mg-6Zn-1Y合金在GPa级超高压下凝固不但可以获得超细的枝晶组织,还可改善枝晶间层片状组织的形态。随着凝固压力的增加,由常压下的晶间网状或带状逐渐过渡到超高压下的"长岛状"以及"粒状"。特别是提高了单位面积上晶间相(含准晶I-Mg3YZn6相)的含量,其体积分数约占40%,同时还形成了纳米级的弥散分布在基体上高Y含量的Mg-Zn-Y三元新相。The solidification path in the Mg-6Zn-1Y alloy was calculated by FactSage thermodynamic software and Mg-database. Thesolidification process and the formation of quasi-crystal phase in the Mg-6Zn-1Y alloy were analyzed using OM, SEM equipped with EDS,XRD, and DSC. The results show that the microstructure of the alloy solidified under the ambient pressure is consisted of the lamellarquasi-crystal I-Mg3YZn6 distributed in the interdendritic region of the coarse α-Mg dendrite and the thermodynamic calculation is wellagreed with the experimental analyses of the solidification process. The microstructure of the super-fined dendrite can be obtained and themorphology of interdendritic lamellar phases can be improved when the alloy solidifies under super-high pressure in the order of GPa. Thetransition of dendritic morphology occurs from interdendritic network or banding to ＂long island＂ as well as ＂granule＂ with the increasingof solidified pressure. In particular, the amount of interdendritic quasi-crystal I-Mg3YZn6 increases remarkably and the volume fraction ofthe phase is up to 40%. Meanwhile, the new ternary Mg-Zn-Y phase with high Y content is dispersively distributed in the matrix with thesize in the order of nanometer.

关 键 词：GPa级超高压 Mg-6Zn-1Y合金 准晶 枝晶组织 

分 类 号：TG111.4[金属学及工艺—物理冶金]