杨玲
,
赵宇宏
,
侯华
,
杨晓敏
稀有金属材料与工程
采用常规凝固技术制备了Mg-45Zn-xY(x=1.0,4.0,5.5,8.0,质量分数,％)合金.利用SEM、EDS、OM、TEM、XRD、DSC和硬度测试技术研究了Y对Mg-45Zn-xY系合金组织及性能的影响,同时对准晶相(Ⅰ-phase)的形成机制进行了分析.结果表明:合金组织主要由a-Mg颗粒或枝晶、花瓣状的Mg3Zn6Y准晶相、层片状的(Ⅰ-phase+α-Mg)共晶组织以及Mg7Zn3相组成;准晶相形貌、含量及分布与Y含量密切相关,随着Y含量的增加,花瓣状准晶相含量逐渐增加,当Y含量为5.5％时,花瓣状准晶相含量最多,合金的硬度达到最大值,HB为1557 MPa,当Y含量为8.0％时,合金中的花瓣状准晶相消失;准晶以层片状共晶组织和花瓣状形式存在,花瓣状的特殊形貌是正二十面体沿五次轴方向生长的结果.
关键词:
Mg-Zn-Y合金
,
常规凝固
,
准晶
,
微观组织
,
性能
LUO Zhiping
,
ZHANG Shaoqing
,
SONG DeyuBeijing Institute of Aeronoutical Materials
,
Beijing
,
100095
,
ChinaTANG Yali
,
ZHAO DongshanZhengzhou Institute of Technology
,
Zhengzhou
,
450002
,
China Manuscript received
,
27 April 1994
金属学报(英文版)
In the as-cast Mg-Zn-Zr-Y alloys, the quasicrystal phases show massive and eutectoid plate morphologies. The selected area dijfraction(SAD) revealed that a large pan of the quasicrystals are face-centered icosahedral (FCI), while a small amout of the quasicrystals belong to the simple icosahedral (SI) phase. It was found that in homogenized alloys, a part of the grain boundry phases was dissolved,and small massive W-phase and lath-shape MgZn_(2) phase dispersedly precipitate in the grains. The transformation of the quasicrystals relates to the temperature. After homogenizing at 360 ℃ , the quasicrystals still present, while after homogenizing at 400 ℃ , the quasicrystals transformed into a new C-type orthorhombic phase witha = 0.975 nm, b = 1.137nm and=0.935 nm.
关键词:
Mg-Zn-Zr-Y alloy
,
null
,
null
