Effect of Zn/Er weight ratio on phase formation and mechanical properties of as-cast Mg-Zn-Er alloys
- 作者：Han Li lihan915@emails.bjut.edu.cn ; Wenbo Du ; duwb@bjut.edu.cn ; Shubo Li ; Zhaohui Wang
- 关键词：Ferrous alloys ; Microstructure ; Mechanical properties
- 刊名：Materials and Design
- 出版年：2012
- 期刊代码：56_02613069
- 类别：ms
- 出版时间：March, 2012
- 卷：35
- 期：Complete
- 页码：259-265
- 文件大小：940 K
摘要
The results of X-ray diffraction (XRD), differential scanning calorimetry (DSC) and microstructure observations have shown that various Zn/Er weight ratio leads to different phase compositions in the investigated alloys. The composition range for the formation of icosahedral quasicrystalline (I-phase) and face-centered cubic phase (W-phase) in Mg-rich corner is obtained. The Zn/Er weight ratio adjusting from10 to 6 results in the formation of I-phase exclusively as main secondary phase in the as-cast Mg-Zn-Er alloys. However, when the ratio is less than 0.8, it is mainly contributed to the precipitation of W-phase. When the ratio is in the range from 1 to 4, I-phase coexisting with W-phase is inclined to be formed. The results of tensile tests suggest that the as-cast Mg-5Zn-5.0Er alloy with I-phase and W-phase possesses the highest ultimate strength (UTS). It is concluded that UTS and elongation rate (ER) of as-cast Mg-Zn-Er alloys with I-phase as the main secondary phase are excellent. The UTS of the alloys with coexistence of I-phase and W-phase show the tendency of increasing firstly then decreasing with the increasing volume fraction of W-phase. The UTS declines when W-phase completely replaces I-phase in the alloy.