第二相和晶界析出特征对7050铝合金晶间腐蚀性能的影响  

Effect of second phase and grain boundary precipitation characteristics on intergranular corrosion properties of 7050 aluminum alloy

作　　者：李明高 孙梅玉 章潇慧 陈朝中 刘嘉仪 邓运来 LI Minggao;SUN Meiyu;ZHANG Xiaohui;CHEN Chaozhong;LIU Jiayi;DENG Yunlai(China Railway Rolling Stock Corporation Academy,Beijing 100071,China;Light Alloy Research Institute,Central South University,Changsha 410083,China;School of Materials Science and Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中车工业研究院有限公司,北京100071 [2]中南大学轻合金研究院,长沙410083 [3]中南大学材料科学与工程学院,长沙410083

出　　处：《航空材料学报》2024年第4期118-127,共10页Journal of Aeronautical Materials

基　　金：国家新材料生产应用示范平台建设项目重点资助项目(TC190H3ZV)。

摘　　要：采用扫描电子显微镜(SEM),电子背散射衍射(EBSD)和透射电子显微镜(TEM)等技术研究Al-Zn-Mg-Cu系合金不同时效制度下形成的晶界析出特征与含Fe第二相(Al_(7)Cu_(2)Fe相)对晶间腐蚀性能的影响。结果表明:时效24 h后的铝合金试样表面尺寸较大的Al_(7)Cu_(2)Fe相Fe含量的变化率最大,而时效60、120 h的试样表面尺寸较小的Al_(7)Cu_(2)Fe相Fe含量变化率较大;随着时效时间的增长,7050铝合金试样中Al_(7)Cu_(2)Fe相引起表面点蚀的时间缩短,晶间腐蚀深度减小,表明其耐晶间腐蚀性能随时效时间的增长而增强;随着时效时间的增长,试样的晶界无沉淀析出带(precipitation-free zone,PFZ)宽度增大,晶界析出物(grain boundary precipitation,GBPs)的形核数减少,间距增大,容易发生晶间腐蚀的晶粒取向逐渐集中。SEM,EBSD and TEM techniques were used to study the effects of grain boundary precipitation characteristics and the Fe-containing second phase(Al_(7)Cu_(2)Fe phase)formed under different aging regimes on the intergranular corrosion properties of Al-Zn-Mg-Cu alloys.The results show that the change rate of Fe content of Al7Cu2Fe phase with large surface size of aluminum alloy specimen after aging at 120℃for 24 h is the largest,while the phase change rates of Fe content of Al_(7)Cu_(2)Fe phase with small size in specimens aging at 120℃for 60 h and 120 h are greater.With the increase of aging time,the corrosion time of surface pitting caused by Al_(7)Cu_(2)Fe phase in 7050 aluminum alloy specimen is shortened,and the depth of intergranular corrosion decreases,indicating that its intergranular corrosion resistance is enhanced with the increase of aging time.In addition,with the increase of aging time,the PFZ(precipitation-free zone)width of the sample increases,the number of nuclei of GBPs(grain boundary precipitation)decreases,the spacing between GBPs increases,and the grain orientation prone to intergranular corrosion is gradually concentrated.

关 键 词：AL-ZN-MG-CU合金 时效时间 晶间腐蚀 Al7Cu2Fe相 晶界析出特征 

分 类 号：V252.2[一般工业技术—材料科学与工程] TG171[航空宇航科学与技术—航空宇航制造工程]