析出相对稀土镁合金腐蚀行为的影响-中国材料进展

文章信息/Info

Title:: Effect of Precipitates on Corrosion Behavior of Rare Earth Magnesium Alloys

Author(s):: KE Jing; GUO Lingtong; Xi ’an University of Architecture and Technology，School of Metallurgical Engineering, Xi ’an 710055, Shaanxi, P. R. China

Keywords:: Mg-Y-Sm-Zn-Zr Magnesium Alloy; precipitates; microstructure; corrosion behavior; corrosion film

摘要:: 镁合金由于其密度低、比强度高、良好的电磁屏蔽性能而被广泛应用在航空航天、汽车、数码等重要领域，但其较差的腐蚀性能使其应用受到限制。稀土元素的结构与镁合金相同，在α-Mg中具有较大的固溶度，形成的金属间第二相可以有效的改善镁合金的腐蚀性能。本文通过X射线荧光光谱仪、光学显微镜、扫描电子显微镜、电化学站测试等测试设备，表征了合金的腐蚀速率，研究了析出相对稀土镁合金腐蚀行为的影响。结果表明，稀土元素Y、Sm在镁合金中形成了(Mg,Zn)3(Y,Sm)和Mg12(Y,Sm)Zn两种析出相，在合金腐蚀过程中(Mg,Zn)3(Y,Sm)相最先被腐蚀，随后是α-Mg基体和Mg12(Y,Sm)Zn相。析出相在合金腐蚀过程中形成了腐蚀产物膜层，增大了合金的阻抗值，腐蚀产物膜层对合金起到了保护作用，有效的降低了合金的腐蚀速率。

Abstract:: Magnesium alloys are widely used in aerospace, automotive, digital and other important fields due to their low density, high specific strength, and good electromagnetic shielding properties, but their poor corrosion properties limit their applications. The structure of rare earth elements is the same as that of magnesium alloys, and has a large solid solubility in α-Mg, and the formed intermetallic second phase can effectively improve the corrosion performance of magnesium alloys. In this paper, the corrosion rate of the alloy was characterized by X-ray fluorescence spectrometer, optical microscope, scanning electron microscope, electrochemical station test and other test equipment, and the influence of precipitation on the corrosion behavior of rare earth magnesium alloy was studied. The results show that rare earth elements Y and Sm form two precipitation phases (Mg,Zn)3(Y,Sm) and Mg12(Y,Sm)Zn in magnesium alloys. During the corrosion process of the alloy，the (Mg,Zn)3(Y,Sm) phase is etched first, followed by the α-Mg matrix and the Mg12(Y,Sm)Zn phase. The precipitates form a corrosion product film during the alloy corrosion process, which increases the resistance value of the alloy. The corrosion product film protects the alloy and effectively reduces the corrosion rate of the alloy.