Microstructure evolution and mechanical properties of Mg–10Gd–3Y–x Zn–0.6Zr alloys
Microstructure evolution and mechanical properties of Mg–10Gd–3Y–x Zn–0.6Zr alloys
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DOI：
10.1557/jmr.2018.100
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发表时间：
2018-06
影响因子：
2.7
通讯作者：
Zhibing Ding;Yu-hong Zhao;Ruopeng Lu;H. Pei;H. Hou
中科院分区：
文献类型：
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作者：
Zhibing Ding;Yu-hong Zhao;Ruopeng Lu;H. Pei;H. Hou
系统地研究了Mg-10Gd-3Y-xZn-0.6Zr(x=0.5、1和1.5wt%)合金在铸态、固溶处理和峰时效条件下的组织演变和力学性能。结果表明，含锌量为0.5%的铸态合金的显微组织为α-Mg、(Mg，Zn)3RE和Mg24(RE，Zn)5相，而含锌量为1.0%和1.5%的铸态合金由α-Mg、(Mg，Zn)3RE和一些层错组成。此外，在锌含量为1.5%的铸态合金中还观察到了18R-LPSO相。LPSO相的形成不仅涉及到堆积顺序的有序，而且涉及到化学成分的有序。固溶处理后，合金中的镁、层错和18R-LPSO相转变为14H-LPSO相。14H-LPSO相对改善材料的力学性能，特别是延性起着重要作用。峰值时效合金中析出了具有BCO结构的β‘相，析出硬化显著提高了合金的抗拉强度，但塑性较差。
The microstructure evolution and mechanical properties of Mg–10Gd–3Y– x Zn–0.6Zr ( x = 0.5, 1, and 1.5 wt%) alloys in the as-cast, solution-treated, and peak-aged conditions have been investigated systematically. The results indicate that the microstructure of the as-cast alloy with 0.5% Zn consists of α-Mg, (Mg,Zn)_3RE and Mg_24(RE,Zn)_5 phases, while the alloy with 1.0 and 1.5% Zn consists of α-Mg, (Mg,Zn)_3RE and some stacking faults. Moreover, 18R-LPSO phases are observed in the as-cast alloy with 1.5% Zn. The formation of LPSO phases involves not only stacking sequence ordered but also chemical composition ordered. After solution treatment, the Mg_24(RE,Zn)_5, (Mg,Zn)_3RE, stacking faults, and 18R-LPSO phases transform into 14H-LPSO phases. The 14H-LPSO phase plays an important role in the improvement of mechanical properties, especially for the ductility. The β′ phase with a bco structure precipitates in the peak-aged alloys results in precipitation hardening, significantly improving the tensile strength, but it leads to poor ductility.