Microstructure and phase transformation of as-cast and annealed Mg–4Zn–1Y alloy containing quasi-crystal phase  

作　　者：Yang Yang Kui Zhang Xing-Gang Li Yong-Jun Li Ming-Long Ma Guo-Liang Shi Jia-Wei Yuan 

机构地区：[1]State Key Laboratory for Fabrication and Processing of Nonferrous Metals, General Research Institute for Nonferrous Metals

出　　处：《Rare Metals》2015年第4期239-244,共6页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.50835002 and 51105102)

摘　　要：By means of optical microscope （OM）, X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM） analyses, the microstructures of as-cast and heat-treated Mg--4Zn-IY （wt%） alloy containing quasi-crystal phase were studied. The microstructure of the as-cast alloy consists of a-Mg solid solution grains, intermetallic particles and eutectic phases （W-phase and 1-phase）, and huge grains with seri- ous dendritic segregation are clearly observed. After heat treatment, phase transformation and dissolution occur in the alloy and many phases remain. When the alloy was treated above 410 ~C, the eutectic phases transform into spherical shape as the I-phase turns to W-phase. After heat treatment for long time, the alloy is over burnt and the W-phase decomposes to Mg-Y binary phase.By means of optical microscope （OM）, X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM） analyses, the microstructures of as-cast and heat-treated Mg--4Zn-IY （wt%） alloy containing quasi-crystal phase were studied. The microstructure of the as-cast alloy consists of a-Mg solid solution grains, intermetallic particles and eutectic phases （W-phase and 1-phase）, and huge grains with seri- ous dendritic segregation are clearly observed. After heat treatment, phase transformation and dissolution occur in the alloy and many phases remain. When the alloy was treated above 410 ~C, the eutectic phases transform into spherical shape as the I-phase turns to W-phase. After heat treatment for long time, the alloy is over burnt and the W-phase decomposes to Mg-Y binary phase.

关 键 词：Mg-Zn-Y alloy Heat treatment MICROSTRUCTURE Phase transformation Icosahedral quasi-crystal 

分 类 号：TG166.4[金属学及工艺—热处理] TG146.22[金属学及工艺—金属学]