Zn含量对Mg-Er-Zn合金铸态组织和力学性能的影响

Effcets of Zn Contents on Microstructures and Properties of Mg-Er-Zn Alloys

采用光学显微镜、X射线衍射、压缩及硬度试验,研究不同Zn含量对Mg98-x Er2Znx合金铸态组织和力学性能的影响。实验结果表明,当x=0,0.5和1.0时,3种合金铸态组织都呈现典型的树枝晶结构。随着Zn含量从0增加到1.0%(原子比)时,合金晶粒也随之逐步细化,二次枝晶臂的间距减小;当Zn含量从1.0%增加到1.5%时,合金却呈现出典型的球状枝晶结构,晶粒粗化。Zn元素含量从0.5%增加到1.5%时,合金中的相组成没有发生变化,依然由α-Mg相,X-Mg12ZnEr相和(Mg,Zn)x Er相组成。随着Zn含量的增加,合金的力学性能呈现出先升高后降低的趋势;当Zn含量为1.0%时,合金的力学性能最好。

The effects of different Zn contents on microstructures and mechanical properties of Mg98-xEr2Znx alloys were investigated by optical microscope, X-ray diffraction, hardness testing and compressive testing machine. The results show that, when x= 0, 0.5 and 1.0, the as-cast alloys present typical dendrite structure. As the zinc content increases from 0 to 1.0% （atomic ratio）, the grains of the alloys refine, the secondary dendrite arm spacing also gradually decreases. When zinc content increases from 1.0% to 1.5%, the alloys present typical globular dendritic structure, the grains gradually coarse. When zinc content increases from 0.5% to 1.5%, the composition of phases don＇t change, still consists of a -Mg, （Mg,Zn） xEr and X-Mgl2ZnEr phase. With the increase of the content of Zn, the mechanical properties increase at first, then decrease. When the Zn content is 1.0%, the mechanical properties of the alloys reache the optimum.