中文摘要：

制备了Mg-x Zn二元合金,研究了不同Zn含量对铸态Mg-x Zn（x=2,4,6,8,10和15,质量分数）合金显微组织和力学性能的影响。结果表明,合金组织主要由基体α-Mg和沿晶界分布的共晶相组成。随着Zn含量增加,共晶相的形态由颗粒状逐渐演变成完全连续的网状,晶粒尺寸得到细化;合金的抗拉强度和伸长率都呈先增加后减小的趋势。当Zn含量为4%时,合金的伸长率获得了最大值,为10.78%,而抗拉强度在Zn含量为6%时达到了210 MPa。Zn含量的逐渐增加使合金的断裂行为由准解理断裂向解理断裂转变。

英文摘要：

The binary Mg-Zn alloys with varied Zn content （2,4,6,8, I0 and 15, in weight） were pre- pared, and microstructure and mechanical properties of the as-cast Mg-xZn alloys were investigated by using an optical mieroscope（OM）, X-ray diffractometer （XRD）, scanning electron microscope （SEM） and mechanical testing. The results reveal that as-cast microstructure of the alloys is composed of matrix a-Mg and eutectic phases distributed along grain boundaries. With increasing in Zn content, the mor- phology of eutectic phase is gradually changed from isolated particles into fully continuous net-work structure, and the grain sizes are decreased. In addition, the tensile strength and elongation of the alloys are increased firstly, and then decreased gradually. The elongation of the alloy with 4 % Zn reaches maxi- mum value of 10.78%, while ultimate tensile strength reaches 210 MPa in the 6% Zn-containing alloy. With the increase of Zn content, the fracture behavior of the alloys is changed from quasi-cleavage to cleavage fracture.