Ca含量对ZM61组织及模拟体液中腐蚀行为的影响

摘要

ZM61-xCa alloys with different contents of Ca were fabricated by using a vacuum induction furnace.As-cast microstructure and crystal structure of the alloys were investigated by using optical metalloscope (OM),scanning electron microscope (SEM) and X-ray diffractometer (XRD).The corrosion behavior of different alloys in simulated body fluid (SBF) was studied via hydrogen evolution and electrochemical test at 37℃.It is shown that the grain size decreases with the addition of Ca.And Ca exists in the precipitation phase primarily.With the increase of Ca content up to 0.5％ (mass fraction,the same below),a continuous network of Ca2Mg6Zn3 is formed along the grain boundary.The corrosion resistance of the alloys is first improved and then decreased with the increase of Ca content.The alloy with 0.5 ％ Ca shows the best corrosion resistance.%通过真空熔炼获得了不同Ca含量的ZM61镁合金,利用光学金相显微镜、扫描电镜和X射线衍射仪分析了其铸态组织结构,并通过37℃下SBF溶液中的析氢试验和电化学测试,研究Ca含量对铸态ZM61合金在仿生环境中腐蚀行为的影响.结果表明,随着Ca的加入,合金的晶粒尺寸细化；Ca在合金中主要存在于Ca2 Mg6 Zn3析出相中,当Ca含量达到0.5％(质量分数,下同)时,这种析出物在晶界形成连续网状；随着Ca含量的增加,合金耐腐蚀性呈先增后减的趋势,Ca含量为0.5％时,合金的耐腐蚀性最佳.