Effect of extrusion on corrosion behavior and corrosion mechanism of Mg-Y alloy  

作　　者：徐宏 张新 张奎 石阳 任霁萍 

机构地区：[1]School of Materials Science and Engineering, North University of China [2]Institute of Thermal Power Generation Technology,China Datang Coporation Science and Technology Research Institute [3]State Key Lab for Fabrication & Processing of Non-ferrous Metals, General Research Institute for Non-ferrous Metals [4]Shenyang Area Military Representative Office of Armored Military Representative Office, Chinese PLA General Armament Department

出　　处：《Journal of Rare Earths》2016年第3期315-327,共13页稀土学报（英文版）

基　　金：supported by the National Key Technology R&D Program of China(2011BAE22B01,2011BAE22B06)

摘　　要：The influences of the hot extrusion process on the microstructure, corrosion behavior and corrosion mechanism for Mg-Y magnesium alloy were studied by means of the microstructure observation, weight loss test, electrochemical test and corrosion morphology test. The results showed that with increasing of the extrusion ratio, the shear flow line on the vertical section of the extruded alloy increased, the shear bands parallel lines became more clearly visible, and a large number of fine equiaxed grains distributed in parallel with the flow lines. The open circuit potential had a certain degree of improvement after extrusion, the open circuit potential increased with increment of extrusion ratio, and the corrosion potential of the vertical section was higher than that of the same alloy in the same compression ratio. The shift rate of the corrosion potential relatively became larger with increasing of the extrusion ratio, and the cathode corrosion current corresponding to the branch migration shifted to the positive direction. The high frequency capacitive arc increased with increment of the extrusion ratio, and the radius of capacitive arc of the vertical section was slightly larger than that of the transverse section. The corrosion morphologies of Mg-0.25 Y alloy were uniform corrosion, and the corrosion morphologies of Mg-（2.5, 5, 8 and 15） were the pitting corrosion and the small range, deep depth localized corrosion.The influences of the hot extrusion process on the microstructure, corrosion behavior and corrosion mechanism for Mg-Y magnesium alloy were studied by means of the microstructure observation, weight loss test, electrochemical test and corrosion morphology test. The results showed that with increasing of the extrusion ratio, the shear flow line on the vertical section of the extruded alloy increased, the shear bands parallel lines became more clearly visible, and a large number of fine equiaxed grains distributed in parallel with the flow lines. The open circuit potential had a certain degree of improvement after extrusion, the open circuit potential increased with increment of extrusion ratio, and the corrosion potential of the vertical section was higher than that of the same alloy in the same compression ratio. The shift rate of the corrosion potential relatively became larger with increasing of the extrusion ratio, and the cathode corrosion current corresponding to the branch migration shifted to the positive direction. The high frequency capacitive arc increased with increment of the extrusion ratio, and the radius of capacitive arc of the vertical section was slightly larger than that of the transverse section. The corrosion morphologies of Mg-0.25 Y alloy were uniform corrosion, and the corrosion morphologies of Mg-（2.5, 5, 8 and 15） were the pitting corrosion and the small range, deep depth localized corrosion.

关 键 词：EXTRUSION Mg-Y alloy corrosion behavior corrosion mechanism rare earths 

分 类 号：TG379[金属学及工艺—金属压力加工] TG146.22[一般工业技术—材料科学与工程]