1 Light Alloy Research Institute, Central South University, Changsha 410083 2 Collaborative Innovation Center of Advance Nonferrous Structural Materials and Manufacturing, Central South University, Changsha 410083 3 Science and Technology on High Strength Structural Materials Laboratory, Central South University, Changsha 410083
Abstract: The effect of trace Co element on the microstructures and corrosion properties of 7056 aluminum alloy was studied by metallographic observation, intergranular corrosion test, electrochemical corrosion test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that the 7056 aluminum alloy with trace Co presented a 22.57% increase of stress corrosion life, an improved fracture strength of stress corrosion from 511 MPa to 559 MPa and a dropped stress corrosion factor from 0.118 to 0.064, compared with the alloy without Co. The 7056 aluminum alloy with Co formed more uniform and fine Al3Zr dispersion phase, which effectively pinned the dislocation and subboundary, made the base keep deformation response structure and small angle grain boundary, thus restrained the recrystallization.and kept fine subcrystalline structure. The precipitation phase in the subgrain boundary is close to that in the intracrystalline, which reduced the electrochemical motivation of intergranular corrosion and improved the resistance to intergranular corrosion. Besides, the area fraction of the precipitated phase at the grain boundary increased, corresponding to the increase of the ratio of anode to cathode in electrochemical reaction process, which resulted in a decrease of the anode current and a decrease of the dissolution rate of the precipitated phase at the grain boundary. The disconti-nuous grain boundary precipitates can block anodic dissolution channels along grain boundaries, slow down the intergranular corrosion and improve the stress corrosion resistance of the alloy.
1 Liu Shengdan, Yin Bangwen, Li Dongfeng, et al. Journal of Central South University (Science and Technology),2016,47(7),2242(in Chinese). 刘胜胆,尹邦文,李东锋,等.中南大学学报(自然科学版),2016,47(7),2242. 2 Liu Shengdan, Li Chengbo, Ouyang Hui,et al. The Chinese Journal of Nonferrous Metals,2013(4),927(in Chinese). 刘胜胆,李承波,欧阳惠,等.中国有色金属学报,2013(4),927. 3 Chinh N Q, Lendval J, Ping D H, et al. Journal of Alloys & Compounds,2004,378(1),52. 4 Xiong Baiqing, Li Xiwu, Zhang Yongan, et al. Materials China,2014,33(2),114(in Chinese). 熊柏青,李锡武,张永安,等.中国材料进展,2014,33(2),114. 5 Zhang Zhihui. Study on quenching sensitivity of 7000 series aluminum alloy. Master’s thesis, Beijing Nonferrous Metals Research Institute, China,2014(in Chinese). 张智慧.7000系铝合金的淬火敏感性研究.硕士学位论文,北京有色金属研究总院,2014. 6 Teng Haitao, Xiong Baiqing, Zhang Yongan, et al. The Chinese Journal of Nonferrous Metals,2015,25(4),852(in Chinese). 滕海涛,熊柏青,张永安,等.中国有色金属学报,2015,25(4),852. 7 Liu Juntao, Zhang Yongan, Li Xiwu, et al. Transactions of Nonferrous Metals Society of China,2014,24(5),1481. 8 Liu Juntao, Zhang Yongan, Li Xiwu,et al. Journal of Aeronautical Materials,2013,33(6),1(in Chinese). 刘俊涛,张永安,李锡武,等.航空材料学报,2013,33(6),1. 9 Han Yi, Li Lian, Deng Zhenzhen, et al. The Chinese Journal of Nonferrous Metals,2011,21(1),179(in Chinese). 韩逸,李炼,邓桢桢,等.中国有色金属学报,2011,21(1),179. 10 Han Yi, Li Lian, Mou Shenzhou,et al. Special-cast and Non-ferrous Alloys,2010,30(10),891(in Chinese). 韩逸,李炼,牟申周,等.特种铸造及有色合金,2010,30(10),891. 11 Guo Fuan, Zhao Yeqing, Li Junpeng, et al. Material Review,2014,28(Z2),463(in Chinese). 郭富安,赵业青,李俊鹏,等.材料导报,2014,28(专辑22),463. 12 Jiang Jianhui, Zheng Ziqiao, Tang Juan, et al. Materials for Mechanical Engineering. 2013,37(4),69(in Chinese). 蒋建辉,郑子樵,唐娟,等.机械工程材料,2013,37(4),69. 13 ШHeйДepГЛ, Xi Guirong, translation. Light Alloy Fabrication Technology,1994,22(11),36(in Chinese). ШHeйДepГЛ,席桂荣译.轻合金加工技术.1994,22(11),36. 14 Wang Yingying . The influence of Co on microstructure and hardenability of 7085 aluminum alloy. Master’s thesis, Central South University, China,2014(in Chinese). 王莹莹.Co对7085铝合金微观组织及淬透性的影响.硕士学位论文,中南大学,2014. 15 Zhang Xinming, Wang Yingying, Liu Shengdan, et al. Rare Metal Materials and Engineering,2014,43(12),2993(in Chinese). 张新明,王莹莹,刘胜胆,等.稀有金属材料与工程,2014,43(12),2993. 16 陈永安. 中国专利, CN101413079,2009. 17 Hu Guiyun, Chen Songyi, Jiang Huili, et al. The Chinese Journal of Nonferrous Metals,2016,26(7),1372(in Chinese). 胡桂云,陈送义,姜慧丽,等.中国有色金属学报,2016,26(7),1372. 18 Li J, Gao X, Jie Z, et al. Acta Metallurgica Sinica,2008,44(9),1031. 19 Chen Songyi, Chen Kanghua, Peng Guosheng, et al. Materials & Design, 2012,35(1),93. 20 Sun Qingqing, Sun Ruiji, Chen Songyi, et al. The Chinese Journal of Nonferrous Metals,2015,25(3),575(in Chinese). 孙擎擎,孙睿吉,陈送义,等.中国有色金属学报,2015,25(3),575. 21 Sun Qingqing, Dong Pengxuan, Sun Ruiji, et al. The Chinese Journal of Nonferrous Metals,2015,25(4),866(in Chinese). 孙擎擎,董朋轩,孙睿吉,等.中国有色金属学报,2015,25(4),866. 22 Trdan U, Grum J. Corrosion Science,2012,59(1),324. 23 Chan H M, Humphreys F J. Metal Science Journal,2013,18(11),527. 24 Fang Huachan, Chen Xuehai, Chen Kanghua. Materials Science and Engineering of Powder Metallurgy,2015,20(5),690(in Chinese). 方华婵,陈学海,陈康华.粉末冶金材料科学与工程,2015,20(5),690. 25 Day M K B, Cornish A J, Dent T P. Metal Science,1969,3(1),175. 26 Minoda T, Yoshida H. Metallurgical and Materials Transactions A,2002,33(9),2891. 27 Tanaka H, Esaki H, Yamada K. Sumitomo Light Metal Technical Reports,2004,45(1),41. 28 Ardo A J D, Townsend R D. Metallurgical Transactions,1970,1(9),2573. 29 Wu Y L, Froes F H, Alvarez A, et al. Materials & Design,1997,18(4-6),211. 30 Xiao Jimei. Metal corrosion under stress, Chemical Industry Press, China,1990(in Chinese). 肖纪美.应力作用下的金属腐蚀,化学工业出版社,1990. 31 Puiggali M, Zielinski A, Olive J M, et al. Corrosion Science,1998,40(4),805. 32 Feng Chun, Liu Zhiyi, Ning Ailin, et al. Journal of Central South University (Science and Technology),2006,37(6),1054(in Chinese). 冯春,刘志义,宁爱林,等.中南大学学报(自然科学版),2006,37(6),1054. 33 Song M, Chen K. Journal of Materials Science,2008,43(15),5265. 34 Sarkar B, Marek M, Starke E A. Metallurgical Transactions A,1981,12(11),1939. 35 Poulose P K, Morral J E, Mcevily A J. Metallurgical Transactions,1974,5(6),1393. 36 Mukhopadhyay A K. Transactions of the Indian Institute of Metals,2009,62(2),113. 37 Wang Feng, Xiong Baiqing, Zhang Yongan, et al. The Chinese Journal of Nonferrous Metals,2007,17(7),1058(in Chinese). 王锋,熊柏青,张永安,等.中国有色金属学报,2007,17(7),1058. 38 Zhang Xinming, Zhang Xiaoyan, Liu Shengdan, et al. Journal of Central South University (Science and Technology),2007,38(5),789(in Chinese). 张新明,张小艳,刘胜胆,等.中南大学学报(自然科学版),2007,38(5),789.