Improvement of Mechanical Properties and Corrosion Resistance by Deformation Induced Precipitation in Al-Zn-Mg-Cu Alloy

Abstract:

A final thermomechanical treatment (FTMT) including peak aging and subsequent dynamic aging was proposed to prepare 7055 Al alloy sheets. The optimization was based on nine well-planned orthogonal experiments. Three main processing conditions in the thermomechanical treatment for obtaining the optimum synthetic properties of 7055 (i.e. preheating temperature, final rolling temperature and deformation degree) were investigated. It was shown that the final rolling temperature is the most important factor among the three parameters, and the optimum properties (yield strength: 651 MPa, ultimate tensile strength: 660 MPa) of 7055 Al alloy sheet can be gained with preheating at 140oC and 40% deformation at 170oC. With dynamic aging, grain boundary precipitates became discontinuous without much coarsening of matrix precipitates, while they were continuously distributed after T6 aging. The present optimal FTMT process can improve the intergranular / exfoliation corrosion resistance without sacrificing the strength compared to T6 tempering. The present FTMT process as a good alternative can produce high-strength Al alloy sheets with high strength and good corrosion resistance efficiently and economically.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 179-190
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.179
• Online since: June 2017
• Authors: Jin Rong Zuo*, Long Gang Hou, Jin Tao Shi, Hua Cui, Lin Zhong Zhuang, Ji Shan Zhang
• Keywords: Al-Zn-Mg-Cu, Exfoliation Corrosion, Intergranular Corrosion, Mechanical Properties, Thermomechanical Treatment

References

[1] A. Heinz, A. Haszler, C. Keidel, S. Moldenhauer, R. Benedictus, W.S. Miller, Recent development in aluminium alloys for aerospace applications, Mater. Sci. Eng., A, 280 (2000) 102-107.

DOI: 10.1016/s0921-5093(99)00674-7

[2] L.M. Wu, W.H. Wang, Y.F. Hsu, T. Shan, L.M. Wu, W.H. Wang, Y.F. Hsu, T. Shan, Effects of homogenization treatment on recrystallization behavior and dispersoid distribution in an Al–Zn–Mg–Sc–Zr alloy, J. Alloys Compd., 456 (2008) 163-169.

DOI: 10.1016/j.jallcom.2007.02.054

[3] Y. Zuo, J. Cui, J. Dong, F. Yu, Effect of low frequency electromagnetic field on the constituents of a new super high strength aluminum alloy, J. Alloys Compd., 402 (2005) 149-155.

DOI: 10.1016/j.jallcom.2005.04.135

[4] S. Maitra, G.C. English, Mechanism of localized corrosion of 7075 alloy plate, Metall. Mater. Trans., A 12 (1981) 535-541.

DOI: 10.1007/bf02648553

[5] M.E. Karabin, F. Barlat, R.W. Schultz, Numerical and experimental study of the cold expansion process in 7085 plate using a modified split sleeve, J. Mater. Process. Technol., 189 (2007) 45-57.

DOI: 10.1016/j.jmatprotec.2007.01.008

[6] R.T. Shuey, F. Barlat, M.E. Karabin, D.J. Chakrabarti, Experimental and Analytical Investigations on Plane Strain Toughness for 7085 Aluminum Alloy, Metall. Mater. Trans., A 40 (2009) 365-376.

DOI: 10.1007/s11661-008-9703-2

[7] B. Sarkar, M. Marek, E. Starke, The effect of copper content and heat treatment on the stress corrosion characteristics of Ai-6Zn-2Mg-X Cu alloys, Metall. Trans. A, 12 (1981) 1939-(1943).

DOI: 10.1007/bf02643806

[8] J. Wloka, T. Hack, S. Virtanen, Influence of temper and surface condition on the exfoliation behaviour of high strength Al–Zn–Mg–Cu alloys, Corros. Sci., 49 (2007) 1437-1449.

DOI: 10.1016/j.corsci.2006.06.033

[9] H. Zhang, L. Li, D. Yuan, D. Peng, Hot deformation behavior of the new Al–Mg–Si–Cu aluminum alloy during compression at elevated temperatures, Mater. Charact., 58 (2007) 168-173.

DOI: 10.1016/j.matchar.2006.04.012

[10] S.C. Bergsma, M.E. Kassner, X. Li, M.A. Wall, Strengthening in the new aluminum alloy AA 6069, Mater. Sci. Eng. A, 254 (1998) 112-118.

DOI: 10.1016/s0921-5093(98)00701-1

[11] H.J. Mcqueen, O.C. Celliers, Application of hot workability studies to extrusion processing: Part II. Microstructural development and extrusion of Al, Al-Mg, AND Al-Mg-Mn Alloys, Can. Metall. Q., 35 (1996) 305-319.

DOI: 10.1016/s0008-4433(96)00011-0

[12] J.R. Davis, Corrosion of aluminum and aluminum alloys, Corrosion of Aluminum & Aluminum Alloys, (1999).

DOI: 10.31399/asm.tb.caaa.9781627082990

[13] B. Cina, Reducing the susceptibility of alloys, particularly aluminium alloys, to stress corrosion cracking, 3856584 (1974).

[14] L. Hai, Z. Ziqiao, W. Zhixiu, Influence of heat treatment regime on microstructures and fracture characteristics of 7055 Al alloy containing Ag [J], Rare. Metal. Mat. Eng, 4 (2005) 025.

[15] J.S. Zhang, Z.G. Chen, J.K. Ren, J.Q. Chen, W. Xiang, F. Liang, Effect of new thermomechanical treatment on microstructure and properties of Al-Zn-Mg-Cu aluminum alloy, T. Nonferr. Metal. soc, 25 (2015) 910-917.

[16] B. Yan, H. -M. Gao, W. Lin, C. Neng, Influence of plasma-MIG welding parameters on aluminum weld porosity by orthogonal test, T. Nonferr. Metal. soc, 20 (2010) 1392-1396.

DOI: 10.1016/s1003-6326(09)60310-1

[17] E. McCafferty, Validation of corrosion rates measured by the Tafel extrapolation method, Corros. Sci., 47 (2005) 3202-3215.

DOI: 10.1016/j.corsci.2005.05.046

[18] J. Waldman, H. Sulinski, H. Markus, The effect of ingot processing treatments on the grain size and properties of Al alloy 7075, Metall. Mater. Trans., B 5(1974) 573-584.

DOI: 10.1007/bf02644652

[19] H. Yoshida, Role of second phase particles and solute atoms in the grain refinement of a 7475 alloy sheet, J. Jpn. I. Met, 41 (1991) 331-337.

[20] R.G. Song, W. Dietzel, B.J. Zhang, W.J. Liu, M.K. Tseng, A. Atrens, Stress corrosion cracking and hydrogen embrittlement of an Al–Zn–Mg–Cu alloy, Acta Mater., 52 (2004) 4727-4743.

DOI: 10.1016/j.actamat.2004.06.023

[21] A.F.O. Jr, M.C.D. Barros, K.R. Cardoso, D.N. Travessa, The effect of RRA on the strength and SCC resistance on AA7050 and AA7150 aluminium alloys, Mater. Sci. Eng. A, 379 (2004) 321-326.

DOI: 10.1016/j.msea.2004.02.052

[22] K. Stiller, P.J. Warren, V. Hansen, J. Angenete, J. Gjønnes, Investigation of precipitation in an Al–Zn–Mg alloy after two-step ageing treatment at 100°C and 150°C, Mater. Sci. Eng. A, 270 (1999) 55-63.

DOI: 10.1016/s0921-5093(99)00231-2

[23] X. Zhang, T.M. Devine, Factors That Influence Formation of AlF3 Passive Film on Aluminum in Li-Ion Battery Electrolytes with LiPF6, J. Electrochem. Soc., 153 (2006) B375-B383.

DOI: 10.1149/1.2218816

[24] J. Ryl, J. Wysocka, M. Jarzynka, A. Zielinski, J. Orlikowski, K. Darowicki, Effect of native air-formed oxidation on the corrosion behavior of AA 7075 aluminum alloys, Corros. Sci., 87 (2014) 150-155.

DOI: 10.1016/j.corsci.2014.06.022

[25] BUZZA D. W., ALKIRE R. C., Growth of corrosion pits on pure aluminium in 1M NaCl, J. Electrochem. Soc., (1995).

DOI: 10.1149/1.2044137

[26] G.S. Frankel, L. Stockert, F. Hunkeler, H. Boehni, Metastable Pitting of Stainless Steel, Corrosion -Houston Tx-, 43 (1987) 429-436.

DOI: 10.5006/1.3583880

[27] X. Zhao, G.S. Frankel, Quantitative study of exfoliation corrosion: Exfoliation of slices in humidity technique, Corrosion Science, 49 (2007) 920-938.

DOI: 10.1016/j.corsci.2006.05.037

[28] I.N. The, G.H. Zhou, L.I. Zhi-Fang, D. Mei, Y.H. Guo, Color-metallographic analysis of the iron-rich phase, Journal of Inner Mongolia Polytechnic University, (2004).

[29] C. Ma, L. Hou, J. Zhang, L. Zhuang, Influence of thickness reduction per pass on strain, microstructures and mechanical properties of 7050 Al alloy sheet processed by asymmetric rolling, Mater. Sci. Eng., A, 650 (2015) 454-468.

DOI: 10.1016/j.msea.2015.10.059

[30] H. Hallberg, B. Svendsen, T. Kayser, M. Ristinmaa, Microstructure evolution during dynamic discontinuous recrystallization in particle-containing Cu, Comp. Mater. sci, 84 (2014) 327-338.

DOI: 10.1016/j.commatsci.2013.12.021

[31] T.C. Tsai, T.H. Chuang, Role of grain size on the stress corrosion cracking of 7475 aluminum alloys, Mater. Sci. Eng. A, 225 (1997) 135-144.

DOI: 10.1016/s0921-5093(96)10840-6

[32] H.I. Aaronson, K.R. Kinsman, K.C. Russell, The volume free energy change associated with precipitate nucleation, Scripta. Mater, 4 (1970) 101-106.

DOI: 10.1016/0036-9748(70)90172-9

[33] A. Deschamps, Y. Brechet, Influence of predeformation and agEing of an Al–Zn–Mg alloy—II. Modeling of precipitation kinetics and yield stress, Acta Mater., 47 (1998) 293-305.

DOI: 10.1016/s1359-6454(98)00296-1

[34] J. Zuo, L. Hou, J. Shi, H. Cui, L. Zhuang, J. Zhang, Precipitates and the evolution of grain structures during double-step rolling of high-strength aluminum alloyand related properties, Acta. Metall. Sin, 52(9) (2016) 1105-1114.

[35] R.E. Sanders, E.A. Starke, The effect of intermediate thermomechanical treatments on the fatigue properties of a 7050 aluminum alloy, Metall. Mater. Trans. A, 9 (1978) 1087-1100.

DOI: 10.1007/bf02652213

[36] Y. Lang, Y. Cai, H. Cui, J. Zhang, Effect of strain-induced precipitation on the low angle grain boundary in AA7050 aluminum alloy, Mater. Des., 32 (2011) 4241-4246.

DOI: 10.1016/j.matdes.2011.04.025

[37] R.Z.T. Z.T. Wang, Handbook of Aluminium Alloy and its Working, Central South University Press, Changsha, (2000).

[38] Y.C. Lin, J.L. Zhang, G. Liu, Y.J. Liang, Effects of pre-treatments on aging precipitates and corrosion resistance of a creep-aged Al–Zn–Mg–Cu alloy, Mater. Des., 83 (2015) 866-875.

DOI: 10.1016/j.matdes.2015.06.029

[39] J.H. Blind, Strain-induced corrosion cracking of low-alloy steels in LWR systems — case histories and identification of conditions leading to susceptibility, Nucl. Eng. des., 91 (1986) 305–330.

DOI: 10.1016/0029-5493(86)90084-1