Microstructure and Mechanical Properties of Mg-Er-Zn Alloys with LPSO Phase

Abstract:

As-cast Mg-3Er-xZn (x = 0, 0.5, 1 and 2 at.%) alloys were prepared by a cast ingot metallurgy process. The effect of Zn contents on the microstructure and phase constitution of the alloys was investigated by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and transmission electronic microscope (TEM). The results revealed that the as-cast Mg-3Er alloy mainly consisted of α-Mg phase and MgEr eutectic phase. Typically, a small amounts of LPSO phase was precipitated at grain boundaries by adding 0.5 at.% Zn into Mg-3Er alloy. With the addition of 1 at.%Zn, the volume fraction of LPSO phase increased obviously. When the addition of Zn increased to 2 at.%, the volume fraction of LPSO phase decreases and Mg₈ZnEr phase forms at grain boundaries. Tensile test indicated that Mg-3Er-1Zn alloy exhibits the excellent mechanical properties. The tensile strength, yield strength and elongation of Mg-3Er-1Zn alloy are 213 MPa, 187.6 MPa and 5.52%, increased by 38.8%, 60% and 3.19%, respectively, corresponding to the alloy without Zn addition. The excellent mechanical properties could be attributed to the introduction of Zn element in alloys, which leads to the strengthening of LPSO phase and grain refinement of α-Mg.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 53-60
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.53
• Online since: June 2017
• Authors: Shu Jing Cui*, Hao Ran Geng, Xin Ying Teng, Xiang Wei Wu, Peng Jia, Chen Wu
• Keywords: Long Period Stacking Ordered (LPSO), Magnesium Alloys, Mechanical Properties, Microstructure

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