Er对铸态AZ91镁合金显微组织和耐腐蚀性能的影响  

Effect of Er on microstructure and corrosion resistance of AZ91 magnesium alloy

作　　者：刘楚明[1,2] 葛位维[1] 李慧中[1,3] 陈志永[1,3] 王荣[2] 高艳蕊[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中国兵器科学研究院宁波分院,宁波315103 [3]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《中国有色金属学报》2009年第5期847-853,共7页The Chinese Journal of Nonferrous Metals

基　　金：国防重大基础研究基金资助项目(2005年)

摘　　要：利用金相显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)、X射线衍射分析、集气法及动电位极化曲线研究了微量Er对铸态AZ91镁合金显微组织和腐蚀性能的影响。结果表明:微量Er可细化AZ91镁合金的铸态组织,当AZ91镁合金中加入Er的含量不高于0.7%(质量分数)时,随着Er含量的增加,镁合金中的γ-Mg17Al12相由粗大、连续块状分布逐渐转变为细小、岛状均匀分布,并且有Al3Er相生成;同时,微量Er也可显著提高铸态AZ91的耐腐蚀性能,当Er含量为0.7%时,合金耐蚀性能大幅度提高,在3.5%(质量分数)NaCl水溶液中浸泡的腐蚀速率为0.54606mg/(cm2·d),仅为常规AZ91镁合金的1/15;微量Er使得AZ91镁合金在3.5%NaCl溶液中的自腐蚀电位升高,自腐蚀电流降低,从而提高AZ91镁合金的耐腐蚀性能。The microstructure and corrosion behavior of AZ91 magnesium alloys with trace addition of Er were investigated by optical microscopy （OM）, scanning electronic microscopy （SEM）, energy-dispersive spectroscopy （EDS）, X-ray diffractometry （XRD）, collecting gas, immersion test and potention dynamic polarization. The results show that with Er addition in the range of 0%-0.7% （mass fraction）, the γ-Mg17Al12 phase is refined with increasing Er addition and disperses well in the matrix, and AlaEr phase forms. The corrosion resistance of alloy is significantly improved. The alloy with 0.7% Er has the best corrosion resistance, and the corrosion rate is 0.546 06 mg/（cm^2.d）, only 1/15 of that of common AZ91 alloy. Trace addition of Er enhances the electrode voltage and lowers the corrosion current of AZ91 alloy in 3.5% NaCl solution, thus improves the corrosion characters of magnesium alloy.

关 键 词：AZ91镁合金 ER 显微组织 腐蚀性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]