Corrosion Resistance of 7475-T7351 Aluminum Alloy Plate for Aviation
Ming LIU1,2,*(), Hui-qu LI1,2, Jun-zhou CHEN1,2, Guo-ai LI1,2, Gao-hong CHEN1,2
1 Beijing Institute of Aeronautical Materials, Beijing 100095, China 2 Beijing Engineering Research Center of Advanced Aluminum Alloys and Applications, Beijing 100095, China
The intergranular corrosion and exfoliation corrosion properties of 7475-T7351 aluminum alloy plate for aviation were investigated, and the corrosion behaviors of the alloy were analyzed by metallographic analysis(MA) and transmission electron microscope(TEM). The results show that no obvious intergranular corrosion is observed, but exfoliation corrosion grade of 7475-T7351 aluminum alloy increases from EA on surface to EC in the core. The exfoliation corrosion of 7475 alloy plate is mainly because of the typical lamellar structure, and the pathway formed by galvanic corrosion on grain boundary. The expansion of grain boundary corrosion product volume produces the wedging force, makes intergranular corrosion grow along the direction in parallel with the surface, and then gradually evolves into exfoliation corrosion. The degree of recrystallization decreases gradually from the surface to center, and the grain length-to-width radio increases, which inclines to exfoliation corrosion and leads to the exfoliation corrosion grade increasing from surface to center.
WANG T , YIN Z M . Research status and development trend of ultra-high strength aluminum alloys[J]. Chinese Journal of Rare Metals, 2006, 30 (2): 197- 202.
WANG H B , HUANG J F , YANG B , et al. Current status and future directions of ultrahigh strength Al-Zn-Mg-Cu aluminum alloys[J]. Materials Review, 2003, 17 (9): 1- 4.
3
HEINZ A , HASZLER A , KEIDEL C , et al. Recent development in aluminum alloys for aerospace applications[J]. Materials Science and Engineering:A, 2000, 280, 102- 107.
doi: 10.1016/S0921-5093(99)00674-7
4
ZANG J X , ZHANG K , DAI S L . Precipitation behavior and properties of a new high strength Al-Zn-Mg-Cu alloy[J]. Transactions of Nonferrous Metals Society of China, 2012, 22 (11): 2638- 2644.
doi: 10.1016/S1003-6326(11)61511-2
5
HIRSCH J , KAHAUSEN K F , LOHTE L . Advances in industrial aluminum research and development[J]. Materials Science Forum, 2002, 396/402, 1721- 1730.
doi: 10.4028/www.scientific.net/MSF.396-402
6
NAUGHTAN D M , WORSFOLD M , ROBINSON M J . Corrosion product force measurements in the study of exfoliation and stress corrosion cracking in high strength aluminum alloys[J]. Corrosion Science, 2003, 45 (10): 2377- 2389.
doi: 10.1016/S0010-938X(03)00050-7
7
ROBERT E , SANDERS J R . Technology innovation in aluminum products[J]. JOM:Journal of the Minerals, Metals and Materials Society, 2001, 53 (2): 21- 25.
doi: 10.1007/s11837-001-0115-7
8
WILLIAM C , JOHN L , JAMES S . Aluminum alloys for aircraft structures[J]. Advanced Materials & Processes, 2002, 160 (12): 27- 29.
9
ZUO Y Y , DAO X L , MENG Y , et al. Effects of prior corrosion with and without stress on the mechanical properties of 7475-T761 aluminum alloy[J]. Acta Metallurgica Sinica, 2015, 28 (5): 608- 613.
doi: 10.1007/s40195-015-0238-4
10
WILLIAMS J C , STARKE Jr E A . Progress in structural materials for aerospace systems[J]. Acta Materialia, 2003, 51 (19): 5775- 5799.
doi: 10.1016/j.actamat.2003.08.023
11
RAJESH K G , HRISHIKESH D , TAPAN K P . Influence of processing parameters on induced energy, mechanical and corrosion properties of FSW butt joint of 7475 AA[J]. Journal of Materials Engineering and Performance, 2012, 21 (8): 1645- 1654.
doi: 10.1007/s11665-011-0074-2
12
SOUZA S D , YOSHIKAWA D S , IZALTINO W A S , et al. Nanostructured surface pre-treatment based on self-assembled molecules for corrosion protection of alclad 7475-T761 aluminum alloy[J]. Materials and Corrosion, 2011, 62 (10): 913- 919.
doi: 10.1002/maco.v62.10
13
TSAI T C , CHANG J C , CHUANG T H . Stress corrosion cracking of superplastically formed 7475 aluminum alloy[J]. Metallurgical and Materials Transactions A, 1997, 28 (10): 2113- 2121.
doi: 10.1007/s11661-997-0168-5
14
TSAI T C , CHUANG T H . Role of grain size on the stress corrosion cracking of 7475 aluminum alloys[J]. Materials Science and Engineering:A, 1997, 225 (1/2): 135- 144.
15
KONG D J , WANG J C . Salt spray corrosion and electrochemical corrosion properties of anodic oxide film on 7475 aluminum alloy[J]. Journal of Alloys and Compounds, 2015, 632, 286- 290.
doi: 10.1016/j.jallcom.2015.01.175
LIU M , ZHANG K , HUANG M , et al. Fatigue damage resistance characteristics of 7475-T7351 aluminum alloy[J]. Chinese Journal of Rare Metals, 2009, 33 (5): 626- 630.
17
段水亮. 合金元素和热处理对7475铝合金组织与性能的影响[D]. 长沙: 中南大学, 2008.
17
DUAN S L. The effects of alloying elements and various heat treatments process on mechanical properties and microstructural evolution of 7475 aluminum alloys[D].Changsha:Central South University, 2008.
CHENG Y S , ZHENG Z Q , LI Q J . Effects of ageing on microstructure and properties of 7475 aluminium alloy[J]. Light Alloy Fabrication Technology, 2001, 29 (6): 40- 44.
LI H H , LIU Z W , DONG C F . Study on aging technology and stress corrosion of 7475 aluminum alloy with thin-wall tube[J]. Light Alloy Fabrication Technology, 2013, 41 (3): 54- 56.
20
SINYAVSKⅡ V S , UIANOVA V V , KALINLIN V D . On the mechanism of intergranular corrosion of aluminum alloys[J]. Protection of Metals, 2004, 40 (5): 481- 490.
doi: 10.1023/B:PROM.0000043067.38199.95
21
RAMGOPAL T , GOUMA P I , FRANKEL G S . Role of grain-boundary precipitates and solute-depleted zone on the intergranular corrosion of aluminum alloy 7150[J]. Corrosion, 2002, 58 (8): 687- 697.
doi: 10.5006/1.3287699
HE Z L , GAO W L , LU Z , et al. Effects of heat treatment on microstructure and properties of 7A85 aluminium alloy[J]. Journal of Materials Engineering, 2015, 43 (8): 13- 18.
doi: 10.11868/j.issn.1001-4381.2015.08.003
23
VALIEV R Z , MURASHKIN Y M , SABIROV I . A nanostructural design to produce high-strength Al alloys with enhanced electrical conductivity[J]. Scripta Materialia, 2014, 76, 13- 16.
doi: 10.1016/j.scriptamat.2013.12.002
24
ROBINSON M J , JACKSON N C . Exfoliation corrosion of high strength Al-Cu-Mg alloys:effect of grain structure[J]. British Corrosion Journal, 2014, 34 (1): 45- 49.
25
KELLY D J , ROBINSON M J . Influence of heat treatment and grain shape on exfoliation corrosion of Al-Li alloy 8090[J]. Corrosion, 1993, 49 (10): 787- 795.
doi: 10.5006/1.3316001
ZHAO F , LU F Y , GUO F A . Comparative analysis of microstructures and properties of two kinds of thick plates of 7050-T7451 aluminum alloy[J]. Journal of Aeronautical Materials, 2015, 35 (2): 64- 71.
doi: 10.11868/j.issn.1005-5053.2015.2.008
NING A L , LIU Z Y , ZHENG Q C , et al. Effects of progressive solution treatment on microstructure and mechanical properties of 7A04 aluminum alloy[J]. The Chinese Journal of Nonferrous Metals, 2004, 14 (7): 1211- 1216.