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将Zn和Y元素以原子比为6∶1的形式加入AM50合金中,并采用金属型铸造成形,利用OM,SEM,EDS,XRD,热分析法及拉伸实验研究了AM50-x(Zn,Y)(x=0,2,3,4,5,质量分数,%)合金的显微组织、凝固行为及力学性能.结果表明:向AM50合金中按原子比为6∶1的形式加入Zn和Y元素后,组织得到明显细化,组织中并未形成Mg3Zn6Y准晶相,而是形成了颗粒状的Al6YMn6相和细小的Al2Y相,其中Al6YMn6相尺寸随着Zn和Y元素含量的增加而增大;当x≥3时,在组织中b相的周围逐渐形成层片状的F-Mg21(Zn,Al)17相,且其数量逐渐增加.热分析结果表明,F-Mg21(Zn,Al)17相约在354℃通过包晶反应形成,其中a-Mg和b相析出温度随着x的增加而降低.由于Al6YMn6相、Al2Y相和F-Mg21(Zn,Al)17相的形成,使得b相的尺寸减小、数量减少;当x=4时,合金组织最为细小,且合金力学性能达到最优,其抗拉强度、屈服强度和伸长率分别为206.63 MPa,92.50 MPa和10.04%.
The Zn and Y elements were added to the AM50 alloy in the atomic ratio of 6:1, and the metal was used for the forming. The mechanical properties of AM50-x (Zn, Y) were investigated by OM, SEM, EDS, Y) (x = 0, 2, 3, 4, 5, mass fraction,%) were studied.The results show that the addition of Zn And Y element, the microstructure is obviously refined, but the Mg3Zn6Y quasicrystal is not formed in the microstructure, but the granular Al6YMn6 phase and the fine Al2Y phase are formed. The size of Al6YMn6 phase increases with the increase of Zn and Y contents (Zn, Al) 17 phase around the b-phase in the microstructure gradually increased when x≥3.The results of thermal analysis showed that the content of F-Mg21 (Zn, Al) 17 is formed by peritectic reaction at about 354 ℃, and the precipitation temperature of a-Mg and b phases decreases with the increase of x. Due to the formation of Al6YMn6, Al2Y and F-Mg21 (Zn, Al) When x = 4, the microstructure is the smallest and the mechanical properties of the alloy are optimized. The tensile strength, yield strength and elongation of the alloy are 206.63 MPa, 92.50 MPa and 10.04%, respectively. .