稀土Y对Mg-5Al-1Sr-2Ca合金组织和耐腐蚀性能的影响(英文)

Microstructure and Corrosion Resistance of Mg-5Al-1Sr-2Ca-XY Alloy

研究了稀土元素Y含量的不同对Mg-5Al-1Sr-2Ca合金微观组织和耐腐蚀性的影响。使用对掺法制备了Mg-5Al-1Sr-2Ca-XY(X=0,0.5,0.7,1.0;质量分数,%)合金。采用光学显微镜(OM)、扫描电镜(SEM)和X射线衍射(XRD)分析了该合金。结果表明,随着Y的加入,合金中出现Al2Y新相,合金晶粒得到细化。当Y含量为0.7%时,合金晶粒最细。但是当Y含量大于0.7%时,晶粒变大,并且不规则。通过静态失重测试和极化曲线法研究了合金的耐腐蚀性。发现随着Y的添加提高了合金的平衡电位和腐蚀电位,耐腐蚀性提高。在本实验范围内,当Y含量为0.7%时,合金的耐腐蚀性最好。

The effects of different contents of Y on microstructures and corrosion resistances of Mg-5Al-l Sr-2Ca alloys were investigated. Mg-SAl-ISr-2Ca-XY（X=O,O.5,0.7,1.O; wt%） alloys were prepared using mixture method and were analyzed by optical microscopy （OM）, scanning electron microscopy（SEM） and X-ray diffraction （XRD）. The results indicate that the grain size can be obviously reduced when the content of Y is 0.7 wt%. With the addition of Y, A12Y phase is formed and acts as the heterogeneous nucleus of a-Mg to enhance the nucleation rate. Simultaneously, A12Y is aggregated in the front of a-Mg and hinders the growth of a-Mg grains. The corrosion resistance of Mg-5Al-ISr-2Ca-XY（X=0,0.5,0.7,1.0; wt%） alloys in 3.5% NaC1 aqueous solution was investigated through static weight-loss test and polarization curve measurement. It is found that due to the addition of Y, the corrosion resistance is improved substantially. Mg-5Al-ISr-2Ca-0.TY alloy has a low corrosion current and the best corrosion resistance among the investigated alloys.