Al-Mg-Zn二十面体准晶合金中的Frank-Kasper相

Frank-Kasper phase in Al-Mg-Zn icosahedral quasicrystal alloys

Frank-Kasper相Mg32（Al，Zn）49是与其准晶相相对应的1／1近似相，它具有二十面体壳层密堆结构。研究了在常规凝固条件下化学成分为A1，Mg40Zn60-x（x=20-45，摩尔分数）合金中Frank-Kasper相的组织形貌。利用光学显微镜、X射线衍射仪及扫描电镜，确定了Frank-Kasper相的组织及成分。结果表明：AlxMg10Zn60-x（x=20～45）合金中均为单相的Frank-Kasper相；随铝含量的增加，其形貌由花瓣状逐渐向“十字架”状组织转变。

Frank-Kasper phase, with an icosahedral close-packed structure, Mg32 （Al, Zn）49 , iS considered as the 1/1 approximant phase analogous to its icosahedral quasicrystal. The morphologies of Frank-Kasper phase, in Alx Mg40 Zr60-x （x= 20 -45, mole fraction） alloys subjected to normal solidification were studied by using optical microscope, X-ray diffraction and scanning electronic microscope. The microstructure and composition of Frank- Kasper phase were determined. It is found that, single Frank-Kasper phase can be obtained in AlxMg40Zn60-x （x= 20-45） alloys, independent of the exact Al content; whereas the morphology of Frank-Kasper phase transforms from petal-like to the cross with increasing Al content.