Abstract

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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

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.