【摘要】 为提高高强镁合金的耐腐蚀性能,选用Sm作为合金化元素添加到ZK30镁合金中。采用真空感应熔炼炉制备了ZK30-xSm镁合金(x=0%,1%,2%,3%,4%,质量分数),并通过光学金相显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、静态失重法以及极化曲线等手段和方法,研究了合金的微观组织、成分和耐腐蚀性能。结果表明,加Sm镁合金主要由α-Mg基体和Mg41Sm5相组成,添加Sm元素以后,合金组织由树枝晶转变为细小的等轴晶,晶粒细化;产生的Mg41Sm5相减缓了ZK30镁合金在3.5%的NaCl溶液中的腐蚀速率,随着Sm含量的增加,腐蚀速率呈先减小后增加的趋势,在Sm含量为1%时,腐蚀速率达到最低,为0.299 5mg/(cm2·h),耐腐蚀性较好,但Sm含量过多时(超过1%),产生了Mg3Sm相,合金的腐蚀速率加快,耐腐蚀性能变差。更多还原

【Abstract】 In order to improve the corrosion resistance of high strength magnesium alloys,Sm was added as alloying element to ZK30 magnesium alloy.ZK30-xSm magnesium alloy(x=0%,1%,2%,3%,4%,mass fraction)was prepared by vacuum induction melting furnace.The microstructure,composition and corrosion resistance of the alloys were studied by means of optical metallographic microscope(OM),scanning electron microscopy(SEM),EDS,XRD,static weight loss method and polarization curves.The results show that the main phases of Mg-3 Zn-xSm-0.5 Zr alloys includeα-Mg matrix and Mg41 Sm5 phase.After adding element Sm,the alloy structure changes from dendrites to fine equiaxed grains,and grains are refined.The generated Mg41 Sm5 phase slows down the corrosion rate of ZK30 magnesium alloy in 3.5% NaCl solution.However,when the content of Sm increases,the corrosion rate of the alloy decreases first and then increases.When the Sm content is 1%,the corrosion rate reaches a minimum of 0.299 5 mg/(cm2· h),and the corrosion resistance is good,but when the Sm content is excessive(more than 1%),the Mg3 Sm phase produced accelerates the corrosion rate of the alloy,and the corrosion resistance is deteriorated.更多还原