摘要
采用Nikon Epiphot型光学显微镜、RigakuD/max-3C型X射线衍射仪(XRD)、带有能谱仪(EDS)的JEOL JSM-6700F型扫描电子显微镜(SEM)研究了高镁、低锌、低钇三元Mg-Zn-Y系合金的铸态组织及其分布特点。在铸态组织中,钇及锌均聚集于晶界。因此在Zn,Y含量相对低时,满足成分条件在晶界形成三元金属间化合物相的成分要求。合金中主要存在的三元相为W(Mg3Y2Zn3)相、Z(Mg3YZn6)相、X(Mg12YZn)相。结合差热分析进一步讨论了合金中相的变化温度。结果表明:W相的共晶熔化温度为520℃;Z相的相变温度为445℃;X相的熔化温度为540℃。
As-cast microstructures and their distribution of Mg-Zn-Y ternary alloy with high magnesium, low zinc and yttrium were examined using Nikon Epiphot optical microscopy ( OM ), RigakuD/max-3C X- ray diffraction (XRD), and JEOL JSM-6700F scanning electron microscopy (SEM) equipped with an energydispersive X-ray spectroscopy (EDS). In the as-cast microstructures, Yttrium and zinc tend to segregate at grain boundaries, therefore meets the compositional condition to form Mg-Zn-Y compounds at grain boundaries even with relatively low content of Y. The principal ternary phase in Mg-Zn-Y alloys may be W-phase (Mg3Y2Zn3), Z-phase (Mg3YZn6) and X-phase (Mg12YZn). Differential thermal analyzer (DTA) shows that the eutectic melting temperature of W-phase is 520℃ ; the phase transformation temperature of Z-phase is 445℃ and the melting temperature of X-phase is 540℃.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2006年第1期86-90,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)
教育部留学回国人员重点基金资助项目
陕西省自然科学基金资助项目(2002E110)
关键词
铸态组织
MG-ZN-Y合金
差热分析
相变点
稀土
as-cast microstructure
Mg-Zn-Y alloy
differential thermal analyzer
phase transition point
rare earths