Effect of Solution Treatment on the Properties and Microstructural Evolution of Al-Zn-Mg-Cu-Er-Zr Alloy

Abstract:

Effect of solution treatment on the properties and microstructural evolution of Al-Zn-Mg-Cu-Er-Zr alloy was investigated by hardness test, conductivity test, exfoliation corrosion test, scanning electron microscope (SEM), transmission electron microscopy (TEM). The results show that the hardness of single-stage solution treated samples first increase and then decrease, the conductivity and volume fraction of the residual phase particles decrease with increasing solution temperature. Compared to conventional multi-stage solution, slow heating process solution treatment can dissolve plenty of residual phases and further improve the hardness and decrease conductivity. Besides, the effect of solution treatment on EXCO is discussed, the result of exfoliation corrosion of SHT8 sample test is judged as EA. Moreover, the effect of the presence of nanometer-sized Al₃(Er,Zr) particles on the microstructural evolution during solution treatment has also been discussed in detailed.

• Periodical: Materials Science Forum (Volume 877)
• Pages: 303-309
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.877.303
• Online since: November 2016
• Authors: Jun Tai Lu*, Hui Huang, Hao Wu, Sheng Ping Wen, Kun Yuan Gao, Zuo-Ren Nie
• Keywords: Al₃(Er,Zr) Particles, Al-Zn-Mg-Cu-Er-Zr Alloy, Microstructural Evolution, Solution Treatment

References

[1] R. Ferragut, A. Somoza, A. Tolley, Microstructural evolution of 7012 alloy during the early stages of artificial ageing, Acta Materialia. 47 (1999) 4355-4364.

DOI: 10.1016/s1359-6454(99)00315-8

[2] B.L. Qu. J.G. Yang, Effects of step quench and aging on mechanical properties and resistance to stress corrosion cracking of 7050 aluminium alloy, Material Transactions. 41 (2000) 783-789.

DOI: 10.2320/matertrans1989.41.783

[3] A. Heinz, A. Haszler, C. Keidel, Recent development in aluminium alloys for aerospace applications, Material Science and Engineering A. 280 (2000) 102-107.

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

[4] J. Dong, J.Z. Cui, F.X. Yu, A new way to cast high-alloyed Al–Zn–Mg–Cu–Zr for super-high strength and toughness, Journal of Materials Processing Technology. 171 (2006) 399-404.

DOI: 10.1016/j.jmatprotec.2005.07.010

[5] P.A. Rometsch, Y. Zhang, S. Knight, Heat treatment of 7xxx series aluminium alloys-Some recent developments, Transactions of Nonferrous Metals Society of China. 24 (2014) 2003-(2017).

DOI: 10.1016/s1003-6326(14)63306-9

[6] D.K. Xu, P.A. Rometsch, N. Birbilis, Improved solution treatment for an as rolled Al-Zn-Mg-Cu alloy. Part I. Characterization of constituent particles and overheating, Material Science and Engineering A. 534 (2012) 234-243.

DOI: 10.1016/j.msea.2011.11.065

[7] Y.L. Deng, L. Wan, Y. Zhang, X.M. Zhang, Evolution of microstructures and textures of 7050 Al alloy hot-rolled plate during staged solution heat-treatments, Journal of Alloys and Compounds. 498 (2010) 88-94.

DOI: 10.1016/j.jallcom.2010.03.117

[8] G.S. Wang, Z.H. Zhao, Y.H. Zhang, J.Z. Cui, Effects of solution treatment on microstructure and mechanical properties of Al-9. 0Zn-2. 8Mg-2. 5Cu-0. 12Zr-0. 03Sc alloy, Transactions of Nonferrous Metals Society of China. 23 (2013) 2537-2542.

DOI: 10.1016/s1003-6326(13)62765-x

[9] G. Liu, J. Sun, C.W. Nan, K.H. Chen, Experiment and multiscale modeling of the coupled influence of constituents and precipitates on the ductile fracture of heat-treatable aluminum alloys, Acta Materialia. 53 (2005) 3459-3468.

DOI: 10.1016/j.actamat.2005.04.002

[10] D.K. Xu, N. Birbilis, D. Lashansky. Effect of solution treatment on the corrosion behaviour of aluminium alloy AA7150: Optimisation for corrosion resistance, Corrosion Science. 53 (2011) 217-225.

DOI: 10.1016/j.corsci.2010.09.015

[11] K.H. Chen, H.W. Liu, Z. Zhang, The improvement of constituent dissolution and mechanical properties of 7055 aluminum alloy by stepped heat treatments, Journal of Materials Processing Technology. 142 (2003) 190-196.

DOI: 10.1016/s0924-0136(03)00597-1

[12] N.M. Han, X.M. Zhang, S.D. Liu, Effect of solution treatment on the strength and fracture toughness of aluminum alloy 7050, Journal of Alloys and Compounds. 509 (2011) 4138-4145.

DOI: 10.1016/j.jallcom.2011.01.005

[13] L.P. Huang, K.H. Chen, S. Li, M. Song, Influence of high-temperature pre-precipitation on local corrosion behaviors of Al–Zn–Mg alloy, Scripta Materialia. 56 (2007) 305-308.

DOI: 10.1016/j.scriptamat.2006.09.028

[14] GB22639-2008, national standard of China. The method for exfoliation corrosion of aluminum alloy.