流场环境中AZ31镁合金的腐蚀行为研究

发布时间：2018-04-10 12:26

本文选题：AZ镁合金 + 腐蚀行为　；参考：《金属学报》2017年10期

【摘要】：采用自主构建的体外模拟流场环境实验平台,通过电化学阻抗谱(EIS)测量、拉伸实验、模拟体液pH值变化测试、SEM观察等方法,对AZ31镁合金在流场环境中的腐蚀行为进行了研究。从腐蚀电化学角度探究了流场中镁合金腐蚀速率与流速的定量关系,并采用ANSYS有限元分析研究了流态与剪切力作用对镁合金不同部位腐蚀差异的影响。结果表明,流场会加速AZ31镁合金的腐蚀,在腐蚀初期,腐蚀电流密度i_(corr)与流场平均流速n之间存在i_(corr)~(-1)=i_c~(-1)+Aν~(-1/2)的关系,其中,ic为不考虑扩散影响时的腐蚀电流密度,A为常数。腐蚀速率随流速增加而增大,且随着腐蚀时间延长,由于腐蚀产物的影响而逐渐偏离i_(corr)~(-1)~n~(-1/2)的线性关系。有限元分析表明,样品不同部位表面流体流态及剪切应力分布不同,局部传质系数K存在显著差异,不同流速下试样边缘部位的传质系数是中间的4~5倍,试样局部腐蚀形貌与剪切应力分布及流态差异相对应。
[Abstract]:The corrosion behavior of AZ31 magnesium alloy in flow field was studied by means of electrochemical impedance spectroscopy (EIS) measurement, tensile test and simulated body fluid pH change test.The quantitative relationship between corrosion rate and flow rate of magnesium alloy in flow field was investigated from the point of view of corrosion electrochemistry, and the effect of flow state and shear force on corrosion difference of magnesium alloy in different parts was studied by ANSYS finite element analysis.The corrosion rate increases with the increase of the flow rate, and with the increase of corrosion time, the linear relationship of iaphne corrrosl / 1 / 1 / 1 / 2 is gradually deviated from the effect of corrosion products.The results of finite element analysis show that the local mass transfer coefficient K is significantly different from the surface fluid flow state and shear stress distribution in different parts of the sample, and the mass transfer coefficient at the edge of the sample is 4 ~ 5 times higher than that in the middle at different velocity of flow.The local corrosion morphology of the specimen corresponds to the distribution of shear stress and the difference of flow state.
【作者单位】：东南大学材料科学与工程学院;
【基金】：国家自然科学基金项目Nos.31570961;51771054 国家重点研发计划项目No.2016YFC1102402~~
【分类号】：TG178

【相似文献】