TEM STUDIES OF THE W PHASE AND ITS ORDERED W'PHASE IN RARE EARTH Mg ALLOYS
(1.Beijing Institute of Aeronautical Materials; Beijing 100095; China;
2.Zhengzhou Institute of Technology; Zhengzhou 450002; China)
2.Zhengzhou Institute of Technology; Zhengzhou 450002; China)
Abstract: By means of transmission electron microscopy(TEM),the W phase and its ordered W' phase in as-cast Mg-Zn-Zr-Y system alloys were studied.The W phase,which distributes along the grain boundaries in the form of a lamellar eutectoid with Mg,is of FCC structure with α= 0.865 nm.The W'phase,which is an ordered structure of the W phase with α=2.055 nm, was found in the alloy with lower Y content.The W and W'phases have a simple orientation relationship of100W//(100)W',010W//(010)W',and001W//001W;but they do not have an orientation relationship with the α-Mg matrix.The results of convergent electron cliffractions(CBD)on these phases show that their point group is m3m and that the space group is Fm3m.
Key words: Mg alloy; rare earth; phase; TEM