AZ91-3Ca镁合金组织结构和电化学行为的研究  

Microstructure and Electrochemical Behavior of AZ91-3Ca Magnesium Alloy

作　　者：王冬晓 王忠军[1] 张涛[1] 褚旭 王洪斌[1] 周乐[1] Wang Dongxiao;Wang Zhongjun;Zhang Tao;Chu Xu;Wang Hongbin;Zhou Le(University of Science and Technology Liaoning,Anshan 114051,China)

机构地区：[1]辽宁科技大学,辽宁鞍山114051

出　　处：《稀有金属材料与工程》2018年第9期2735-2742,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51374128;51404137);辽宁科技大学研究生教育改革与科技创新创业项目(LKDYC201609)

摘　　要：利用扫描电镜(SEM)、X射线衍射仪(XRD)以及电化学测试法和失重法研究了铸态AZ91-3Ca镁合金分别在退火处理前后的相组成以及不同退火处理条件下的腐蚀行为。结果表明,铸态AZ91-3Ca镁合金主要由基体α-Mg相和沿着晶界附近分布的网状共晶相组成。共晶相中含有α-Mg相,实心块状β-Mg_(17)Al_(12)相和鱼骨状(Mg,Al)_2Ca相等。300和400℃退火处理后合金的组织结构没有明显变化,但是在较高退火温度500℃下保温2.0 h后,β-Mg_(17)Al_(12)相溶解促进了一种含有Mg,Al,Zn,Ca 4种元素的四元相的生成。在500℃保温16.0 h后,基体中Al元素含量最多,且分布均匀,在NaCl水溶液中耐蚀性能最佳,其自腐蚀电位为-1330mV,电流密度为1.222×10^(-4)A/cm^2,腐蚀速率为0.11 mg/cm^2·h。The microstructure of as-cast AZ91-3 Ca magnesium alloy before and after annealing treatment and the corrosion behavior under different annealing conditions were studied by scanning electron microscopy（SEM）,X-ray diffractometer（XRD）,electrochemical test and mass loss method.The results show that the as cast AZ91-3 Ca alloy is mainly composed of matrix a-Mg phase and a network eutectic phase along the grain boundaries.The eutectic phase contains a-Mg phase,a solid block β-Mg17Al12 phase and a Mg（Al）2Ca phase.The microstructures of the alloys annealed at 300 ℃ and 400 ℃ have no obvious change.After annealing at 500 ℃ for 2.0 h,the solution of β-Mg17Al12 phase promotes the precipitation of Mg,Al,Zn and Ca to form a new phase. After annealing at 500 ℃ for 16.0 h,the content of Al in the matrix is the most with uniform distribution and the corrosion resistance is the best in NaCl aqueous solution,for example its corrosion potential is –1330 mV,the current density 1.222 × 10^-4A/cm^2,and the corrosion rate 0.11 mg/cm^2·h.

关 键 词：AZ91-3Ca 退火 组织 相 腐蚀 

分 类 号：TG146.22[一般工业技术—材料科学与工程]