摘要
通过光学显微镜（OM）和扫描电子显微镜（SEM）观察了Mg-x Zn-y Gd（x=1~3,y=0~3）合金的挤压态组织及腐蚀形貌。结果表明：挤压态组织得到细化,平均晶粒尺寸从Mg-3Zn合金的（30±3）μm降到Mg-3Zn-1Gd合金的（10±2）μm,说明挤压过程发生了明显的动态再结晶,第二相沿挤压方向趋于带状分布。Mg-x Zn-y Gd合金的腐蚀以点蚀为主,在浸泡的时间段内,Mg-3Zn-2Gd合金的腐蚀速率最快,Mg-3Zn合金的腐蚀速率最低。经固溶处理后,Mg-3Zn-2Gd和Mg-3Zn-3Gd合金的腐蚀速率由原来的（0.605±0.025）和（0.352±0.021）mg/（cm^2·h）分别降为（0.085±0.010）和（0.167±0.020）mg/（cm^2·h）。随着Zn含量的增加,自腐蚀电流密度逐渐降低,高频区容抗半环逐渐增大;随着Gd含量的增加,自腐蚀电流密度逐渐先升高后降低,高频区容抗半环先降低后升高。Mg-3Zn合金的自腐蚀电流密度最小,为8.65×10-3（m A/cm^2）;而其Faraday电阻Rt最大,为3312Ω。
The microstructure and corrosion morphology of extruded alloys Mg-x Zn-y Gd（x=1~3,y=0~3） were observed by optical microscopy（OM）, scanning electron microscopy（SEM）. Results show that after extrusion the microstructure of the alloys is obviously refined and further refined by Gd addition, i.e. the average grain size decreases from（30±3） μm for Mg-3Zn to（10±2） μm for Mg-3Zn-3Gd. The dynamic recrystallization occurs during the extrusion, while the second phase particles tend to distribute as belts along the extrusion direction. Mg- x Zn- y Gd alloy is sensitive to pitting corrosion in the Hank＇s solution. Among others the corrosion of Mg- 3Zn- 2Gd is the fastest,while that of Mg-3Zn is the slowest. After solid solution treatment, the corrosion rate of Mg-3Zn-2Gd and Mg- 3Zn- 3Gd decreases from（0.605 ± 0.025） and（0.352 ± 0.021） mg/（cm^2·h） to（0.085±0.010） and（0.167±0.020） mg/（cm^2·h） respectively. With increasing Zn content the corrosion current density decreases and the high- frequency capacitance increases gradually; with the increaseof Gd content, the corrosion current density and high-frequency capacitance of the alloys rise firstly and then reduce gradually. Mg-3Zn alloy exhibits aminimum corrosion current density（8.65×10-3m A/cm^2）and a maximum Faraday resistance Rt（3312 Ω）.
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2016年第3期267-272,共6页
Journal of Chinese Society For Corrosion and Protection
基金
广东省中国科学院全面战略合作项目(2011A090100004)
广东省产学研重大项目(2010A090200078)
天河区科技攻关项目(201406YG069)资助
