摘要
采用光学显微镜、扫描电镜等研究了经不同温度固溶及时效处理后Mg-9Gd-1Zn-0.2Ca合金的显微组织,利用质量损失法、析氢法和电化学法测试了热处理后合金在模拟体液中的腐蚀性能。结果表明:经过固溶与时效处理之后,合金组织呈树枝状,在晶界或晶粒内部观察到层片状长周期堆垛有序(LPSO)结构;随着固溶温度的升高,共晶相逐渐减少,而晶粒内逐渐析出块状的析出相。由质量损失法和析氢法可知,随着固溶温度的增加,合金的腐蚀速率先增加后降低;固溶温度分别为370、420、470和520℃的合金的腐蚀电流密度分别为3.18×10^-4、5.89×10^-4、2.91×10^-4和2.74×10^-4 A·cm^-2,与浸泡法得到的趋势一致。不同温度固溶处理的合金在模拟体液(SBF)中的腐蚀速率从高到低的顺序为:420℃>370℃>470℃>520℃,均低于铸态合金的腐蚀速率,且520℃固溶处理的合金的腐蚀速率最小,约为铸态合金腐蚀速率的1/10,表明T6处理可显著提高合金的耐蚀性能。
Microstructure of Mg-9 Gd-1 Zn-0.2 Ca biological magnesium alloy after solid solution treatment at different temperatures for 6 h and then aging at 200℃for 8 h was studied by means of optical microscope and scanning electron microscopy,and the corrosion properties of the alloy after heat treatment immersed in simulated body fluid were tested by mass loss method,hydrogen evolution method and electrochemical method.The results show that after solid solution and aging treatment,the microstructure of the alloy is dendritic,and the lamellar long-period stacking ordered(LPSO)structure is observed at grain boundaries or within grains.With the increase of the solid solution temperature,the eutectic phase gradually decreases,while the bulk precipitated phase gradually precipitates in the grains.The mass loss method and hydrogen evolution method show that the corrosion rate of the alloy increases first and then decreases with the increase of the solid solution temperature,and the corrosion current density of the alloy with the solution temperature of 370℃,420℃,470℃and 520℃is 3.18×10^-4,5.89×10^-4,2.91×10^-4 and 2.74×10^-4 A·cm^-2,respectively,which is consistent with the trend obtained by the immersion method.The corrosion rate of the alloy after solid solution treatment at different temperatures in simulated body fluid(SBF)from high to low is:420℃>370℃>470℃>520℃,which is lower than that of the as-cast alloy,and the alloy after solid solution treatment at 520℃has the smallest corrosion rate,which is about 1/10 of that of the as-cast alloy,indicating that T6 treatment can significantly improve the corrosion resistance of the alloy.
作者
夏玉冰
张丽
吴丰
汪荣香
章晓波
XIA Yu-bing;ZHANG Li;WU Feng;WANG Rong-xiang;ZHANG Xiao-bo(School of Materials Science and Engineering,Nanjing Institute of Technology,Nanjing 211167,China;Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology,Nanjing 211167,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2020年第9期51-58,共8页
Transactions of Materials and Heat Treatment
基金
江苏高校自然科学研究重大项目(18KJA430008)
江苏省大学生创新创业训练计划项目(201911276032Y)。
关键词
生物医用镁合金
模拟体液
热处理
腐蚀性能
biomedical magnesium alloy
simulated body fluid
heat treatment
corrosion property
