阶梯模冷却Mg_(68)Zn_(29)Y_3合金的组织及准晶相的形成  

Microstructures and Formation of Quasicrystal Phase in As-cast Mg_(68)Zn_(29)Y_3 Alloy Cooling with Step Die

作　　者：史菲[1,2] 王文博[3] 郭学锋[2] 张忠明[2] 

机构地区：[1]哈尔滨工业大学(威海)材料科学与工程学院,山东威海264209 [2]西安理工大学材料科学与工程学院,陕西西安710048 [3]西北工业大学材料科学与工程学院,陕西西安710072

出　　处：《中国稀土学报》2010年第1期85-89,共5页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金资助项目(50271054);陕西省自然科学基金资助项目(2002E110);陕西省教育厅回国留学人员基金项目资助

摘　　要：采用五层阶梯形模具冷却方法在Mg68Zn29Y3合金中制备了二十面体准晶相(I相)。通过扫描电镜、能谱分析仪和透射电子显微分析技术,观察了合金凝固组织和准晶相的形貌,并确定了准晶相成分及结构。结果表明:Mg68Zn29Y3三元合金在普通凝固-阶梯模冷却过程中,冷却速度对准晶相形貌、数量、大小和分布存在较为显著的影响;随着冷速的降低,准晶相的生长方式由细小弥散演变为粗大碎化,准晶晶粒尺寸由20μm逐渐长大至100μm以上;准晶相通过包晶反应形核、长大;合金凝固组织为MgZn+α-Mg+Zn60Mg30Y10。Mg68Zn29Y3 alloy with stable icosahedral quasicrystals were prepared by cast method cooling with a metal step die. The microstructures, composition and phases of the Mg68Zn29Y3 alloy were analyzed by SEM and EDS. And the icosahedral quasicrystalline structure was identified by TEM. Results showed that the morphology, amount, distribution and grain size of I-phases were influenced by the cooling rate.The typical microstructures of I-phases were petal shaped , pentagon and hexagon. With cooling rate decreasing, I-phases changed from dispersion and fine to fragmentation and coarse, and the grain size grew up from 20 to 100 μm gradually, until crushing to block quasicrystal. The microstructures of the alloy consisted of MgZn ＋ α-Mg ＋ Zn60Mg30Y10 （I-phase）.

关 键 词：阶梯模 Mg—Zn—Y合金 二十面体准晶 冷却速度 稀土 

分 类 号：TG146[一般工业技术—材料科学与工程]