摘要
Al-Mg合金常用于海洋工程装备等领域,长期受到海洋大气的腐蚀,因此如何提升Al-Mg合金的防腐性能有着重大的意义。本文采用晶间腐蚀、电化学腐蚀等实验研究不同含量的Sc对Al-6Mg合金非熔化极惰性气体保护电弧焊(Tungsten Inert Gas Welding,TIG)接头腐蚀行为的影响,并利用电子背散射衍射(Electron Back Scatter Diffraction,EBSD)、透射电子显微镜(Transmission Electron Microscope,TEM)等表征手段分析原因。结果表明:Sc元素与α-Al基体形成共格的Al_(3)Sc粒子,可以钉扎晶界,抑制合金发生再结晶,细化晶粒,保持较高的小角度晶界占比,影响β-Al_(3)Mg_(2)相的析出形貌,耐腐蚀性能得到提升。在晶间腐蚀实验中,Al-6Mg-0.20Sc焊缝区(Weld Zone,WZ)腐蚀的痕迹最浅,抗晶间腐蚀性能最优;在电化学腐蚀实验中,Sc元素含量的增加导致接头各个区域的腐蚀电位正方向移动,接头的腐蚀敏感性降低,Al-6Mg-0.20Sc WZ区的腐蚀电位最高,耐腐蚀性能优异,与晶间腐蚀实验结果一致。
Al-Mg alloys find widespread application in marine engineering equipment and other relevant fields,where they are exposed to prolonged corrosion in the marine atmosphere.Consequently,enhancing the corrosion resistance of Al-Mg alloys assumes paramount significance.The influence of Scandium(Sc)content on the corrosion behavior of TIG-welded joints in Al-6Mg alloy was investigated through comprehensive experimental studies employing electron back scatter diffraction(EBSD),transmission electron microscopy(TEM),and assessments of intergranular and electrochemical corrosion.The results reveal that the addition of Sc forms coherent Al_(3)Sc particles within theα-Al matrix.These particles serve as effective grain boundary pinning sites,effectively suppressing recrystallization and facilitating grain refinement.Furthermore,they contribute to an increased proportion of low-angle grain boundaries.The presence of Sc also impacts the precipitation morphology of theβ-Al_(3)Mg_(2) phase.Consequently,the incorporation of Sc significantly enhances the intergranular corrosion resistance of the alloy.Specifically,in the intergranular corrosion experiments,the Al-6Mg-0.20Sc alloy exhibits the shallowest depth of corrosion tracks in the weld zone(WZ),indicating its superior intergranular corrosion resistance.Moreover,the increase in Sc content results in a positive shift in the corrosion potential across all regions of the joint in the electrochemical corrosion experiments.This shift indicates a reduced susceptibility to corrosion,and the Al-6Mg-0.20Sc alloy exhibits the highest corrosion potential in the WZ,demonstrating its superior corrosion resistance.These findings are consistent with the results obtained from the intergranular corrosion experiments.
作者
蔡奇峰
刘惠
张伟程
曹庚
刘延
常志龙
张华
Cai Qifeng;Liu Hui;Zhang Weichang;Cao Geng;Liu Yan;Chang Zhilong;Zhang Hua(School of Mechanical Engineering,Beijing Institute of Petrochemical Technology,Beijing 102611,China;Beijing Advanced Aluminum Alloy Materials and Application Engineering Technology Research Center,Beijing 100095,China;Tianjin Hangyu Zhuoran Technology Co.,Ltd.,Tianjin 301700,China)
出处
《中国稀土学报》
北大核心
2025年第6期1282-1291,共10页
Journal of the Chinese Society of Rare Earths
基金
北京市属高校分类发展项目(11000023T000002199202)资助。
关键词
铝镁合金
钪
晶间腐蚀
电化学腐蚀
TIG焊
aluminum-magnesium alloy
Sc
intergranular corrosion
electrochemical corrosion
TIG welding
