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镁合金板材具有非常优良的力学性能和耐腐蚀性能,其应用需求日益增大。为进一步提高镁合金板材的性能,通过金相显微镜(OM)、扫描电子显微镜(SEM),电子背散散衍射(EBSD)、力学性能测试、析氢腐蚀、失重腐蚀、电化学极化测试和电化学阻抗测试等手段,研究了变形程度对Mg-5Al-0.4Mn-0.8Ca合金显微组织、力学性能和耐腐蚀性能的影响。结果表明,挤压比的升高导致合金晶粒明显细化,合金组织均匀程度降低。随着挤压比的升高,合金强度略有提高,塑性大幅度提高。合金析氢量、腐蚀失重程度和电化学腐蚀电流密度也随着挤压比的升高而升高,导致合金耐腐蚀性能降低。当挤压比为9时,合金的组织均匀和织构弱化使其具有最佳的耐腐蚀性能,合金腐蚀电流密度和腐蚀失重分别为11.26μA·cm-2和19.01 mg·cm-2·d-1。
Magnesium alloy sheet has very good mechanical properties and corrosion resistance, its application is increasing demand. In order to further improve the properties of magnesium alloy sheets, the properties of the magnesium alloy sheets were characterized by OM, SEM, EBSD, mechanical property test, hydrogen evolution, weight loss corrosion, electrochemical polarization test and electro- Chemical resistance test and other means to study the deformation degree of Mg-5Al-0.4Mn-0.8Ca alloy microstructure, mechanical properties and corrosion resistance. The results show that the increase of the extrusion ratio leads to the grain refinement of the alloy and the decrease of the homogeneity of the alloy structure. With the extrusion ratio increased, the alloy slightly increased strength, plastic greatly increased. The hydrogen evolution rate, the degree of corrosion loss and the electrochemical corrosion current density also increase with the increase of the extrusion ratio, which leads to the decrease of corrosion resistance of the alloy. When the extrusion ratio is 9, the microstructure and weakened structure of the alloy have the best corrosion resistance. The corrosion current density and corrosion loss of the alloy are 11.26μA · cm-2 and 19.01 mg · cm-2 · d -1.