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采用离心铸造法和金属型重力铸造法制备了Mg-6wt%Zn-1wt%Y-0.5wt%Zr(简写为ZW61,下同)合金,比较了合金的铸态显微组织及力学性能。结果表明,离心铸造镁合金的晶粒组织得到明显细化,力学性能得到显著提高。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)研究了ZW61合金的显微组织相组成,基体相均为α-Mg相,ZW61合金的第二相由I相(Mg3Zn6Y)和W相(Mg3Zn3Y2)组成。根据ImageJ软件分析,离心铸件第二相的面积分数比金属型铸件的小,离心铸造中共晶转变L→α-Mg+W和共析转变L+W→α-Mg+I被抑制,导致I、W相减少,形成以过饱和初生相α-Mg为主的凝固组织。离心铸件的塑性特征优于金属型铸件。
The alloy Mg-6wt% Zn-1wt% Y-0.5wt% Zr (abbreviated as ZW61, the same below) was prepared by centrifugal casting and metal gravity casting. The as-cast microstructure and mechanical properties of the alloy were compared. The results show that the grain structure of the centrifugal casting magnesium alloy is obviously refined and the mechanical properties are obviously improved. The microstructure and phase composition of ZW61 alloy were investigated by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The matrix phase was α-Mg phase. The second phase of ZW61 alloy was composed of phase I (Mg3Zn6Y) and W phase (Mg3Zn3Y2). According to ImageJ software analysis, centrifugal casting second phase area fraction than the metal-type castings small, centrifugal casting L → α-Mg + W eutectic transformation and eutectoid transformation L + W → α-Mg + I was inhibited, resulting in I , W phase decreased to form a supersaturated primary phase α-Mg-based solidification organization. The plasticity of centrifugal castings is better than that of metal castings.