凝固条件对Mg-Zn-Y合金中长周期堆垛结构的影响  

Effect of solidification conditions on the formation and structures of long period stacking structures in the Mg-Zn-Y alloys

作　　者：付建强[1] 孙威[1] 武慧敏[1] 谢中柱[1] 

机构地区：[1]北京工业大学固体微结构与性能研究所,北京100022

出　　处：《电子显微学报》2007年第5期415-418,共4页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(No.50571002).~~

摘　　要：应用透射电镜研究了快速凝固,常规凝固以及热处理后Mg97Zn1Y2合金中长周期堆垛结构(LPS)的形成、结构和变化特征。结果表明,快速凝固带状材料中,18R类型的LPS首先在网状第二相中形成,573K时效20h后,18R有向6H转变的趋势。铸态合金中LPS主要为6层堆垛结构,这种结构在573K时效50h后仍然保持稳定。铸态合金在823K热处理10h后,LPS趋于溶解,但镁基体中仍可观察到6层堆垛的LPS的存在。通过不同的凝固和热处理过程,可以获得不同结构和分布状态的LPS。　Electron microcopy has been applied to study formation,structures and structural changes of long period stacking structures（LPSs）in as-spun,as-solidified and heat-treated Mg_ 97Zn_1Y_2 alloys.The results show that the LPS structure of 18R type can form from second phases with a network distribution in the as-spun alloy.It appears that a 18R-to-6H structural transition occured when annealing the as-spun alloy at 573 K for 20 hrs.The LPS formed in the as-solidified alloy has a 6-layer periodic structure;it remained stable at 573 K for 50 hrs.When annealing at 823 K for 10 h,LPSs with 6-layer stacking structure still remained even though dissolution of LPS already taken place at this stage.It is believed that structural types and distribution for LPSs in Mg-Zn-Y alloys are controllable through changing of solidification conditions and subsequent heat treatments.

关 键 词：Mg97Zn1Y2 长周期堆垛结构 凝固条件 热处理 电子显微术 

分 类 号：TG244.3[金属学及工艺—铸造]