Skip to main content
SpringerLink
Log in

Influence of Aging Treatments on Alterations of Microstructural Features and Stress Corrosion Cracking Behavior of an Al-Zn-Mg Alloy

  • Published:
Journal of Materials Engineering and Performance Aims and scope Submit manuscript

Abstract

7xxx series Al-Zn-Mg-(Cu) alloys have higher strength in their peak-aged (T6) states compared with other age-hardenable aluminum alloys; however, the maximum strength peak-aged state is more susceptible to stress corrosion cracking (SCC) which leads to catastrophic failure. The over-aged (T7) temper with 10-15% lower strength has higher resistance to SCC requiring oversized structural aerospace component applications. The medium-strength AA7017 Al-Zn-Mg weldable alloy without Cu is also prone to SCC under certain environmental conditions. In the present investigation, the SCC behaviors of an AA7017 Al-Zn-Mg alloys of different tempers have been assessed. Specific aging schedules have been adapted to an AA7017 alloy to produce various tempers, e.g., under-, peak-(T6), over-(T7), and highly over-aged tempers. Artificial aging behavior of the AA7017 alloy has been characterized by hardness, electrical conductivity measurements, x-ray diffraction, differential scanning calorimetry, and electrochemical studies. Slow strain rate test technique was used to assess the SCC behaviors of the AA7017 alloys of under-, T6, T7, and highly over-aged tempers in 3.5 wt.% NaCl solution at free corrosion potential (FCP) and at applied anodic potential, as well. Results revealed that the AA7017 alloy tempers are not susceptible to SCC in 3.5 wt.% NaCl solution at FCP, but severely damaging to SCC at applied anodic potentials. Microstructural features, showing a non-recrystallized grain structure and the presence of discrete, widely spaced, not-interconnected η precipitates at the grain boundaries, are the contributive factors by virtue of which the alloy tempers at FCP did not exhibit SCC. However, the applied anodic potential resulted in rapid metal dissolution from the grain boundary region and led to SCC. The local anodic dissolution (LAD) is believed to be the associated SCC mechanism.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12

Similar content being viewed by others

References

  1. Z. Huda and P. Edi, Materials Selection in Design of Structures and Engines of Supersonic Aircrafts: A Review, Mater. Des., 2013, 46(April), p 552–560

    Article  Google Scholar 

  2. E.A. Starke, Jr., and J.T. Staley, Application of Modern Aluminium Alloys to Aircraft, Prog. Aerosp. Sci., 1996, 32(2–3), p 131–172

    Article  Google Scholar 

  3. J.C. Williams and E.A. Starke, Jr., Progress in Structural Materials for Aerospace Systems, Acta Mater., 2003, 51(19), p 5775–5799

    Article  Google Scholar 

  4. I.J. Polmear, Light Alloys-Metallurgy of the Light Metals, 2nd ed., Edward Arnold, London, 1989, p 18–143

    Google Scholar 

  5. A. Heinz, A. Haszler, C. Keidel, S. Moldenhauer, and R. Benedictus, Recent Development in Aluminium Alloys for Aerospace Applications, Mater. Sci. Eng. A, 2000, 280(1), p 102–107

    Article  Google Scholar 

  6. J.C. Werenkiold, A. Deschamps, and Y. Brechet, Characterization and Modeling of Precipitation Kinetics in an Al-Zn-Mg Alloy, Mater. Sci. Eng. A, 2000, 293(1–2), p 267–274

    Article  Google Scholar 

  7. K. Stiller, P.J. Warren, V. Hansen, J. Angenete, and J. Gjønnes, Investigation of Precipitation in an Al-Zn-Mg Alloy After Two-Step Ageing Treatment at 100° and 150°C, Mater. Sci. Eng. A, 1999, 270(1), p 55–63

    Article  Google Scholar 

  8. J. Buha, R.N. Lumley, and A.G. Crosky, Secondary Ageing in an Aluminum Alloy 7050, Mater. Sci. Eng. A, 2008, 492(1–2), p 1–10

    Article  Google Scholar 

  9. M.O. Speidel, Stress Corrosion Cracking of Aluminium Alloys, Metall. Trans. A, 1975, 6(4), p 631–651

    Article  Google Scholar 

  10. H. Fooladfar, B. Hashemi, and M. Younesi, The Effect of the Surface Treating and High Temperature Ageing on the Strength and SCC Susceptibility of 7075 Aluminium Alloy, J. Mater. Eng. Perform., 2010, 19(6), p 852–859

    Article  Google Scholar 

  11. B. Cina, Reducing the Susceptibility of Alloys Particularly Aluminium Alloys to Stress Corrosion Cracking, US Patent, 3856584, 24 Dec 1974

  12. L.P. Huang, K.H. Chen, and S. Li, Influence of Grain-Boundary Pre-precipitation and Corrosion Characteristics of Inter-granular Phases on Corrosion Behaviours of an Al-Zn-Mg-Cu Alloy, Mater. Sci. Eng. B, 2012, 177(11), p 862–868

    Article  Google Scholar 

  13. D. Najjar, T. Magnin, and T.J. Warne, Influence of Critical Surface Defects and Localized Competition Between Anodic Dissolution and Hydrogen Effects During Stress Corrosion Cracking of a 7050 aluminium alloy, Mater. Sci. Eng. A, 1997, 238(2), p 293–302

    Article  Google Scholar 

  14. R.G. Song, W. Dietzel, B.J. Zhang, W.J. Liu, M.K. Tseng, and A. Atrens, Stress Corrosion Cracking and Hydrogen Embrittlement of an Al-Zn-Mg-(Cu) Alloy, Acta Mater., 2004, 52(4), p 4727–4743

    Article  Google Scholar 

  15. M.B. Kanan, V.S. Raja, R. Raman, and A.K. Mukhopadhay, Influence of Multistep Ageing on Stress Corrosion Cracking Behaviour of Aluminium Alloy, Corrosion, 2003, 59(10), p 881–889

    Article  Google Scholar 

  16. R.K. Viswanadham, T.S. Sun, and J.A.S. Green, Grain Boundary Segregation in Al-Zn-Mg Alloys—Implications to Stress Corrosion Cracking, Metall. Trans. A, 1980, 11(1), p 85–89

    Google Scholar 

  17. J. Albrecht, I.M. Bernstein, and A.W. Thompson, Thermotransport of Hydrogen and Deuterium in Vanadium, Niobium, and Tantalum, Metall. Trans. A, 1982, 13, p 811–820

    Article  Google Scholar 

  18. L.M. Wu, W.H. Wang, Y.F. Hsu, and S. Trong, Effects of Microstructure on the Mechanical Properties and Stress Corrosion Cracking of an Al-Zn-Mg-Sc-Zr Alloy by Various Temper Treatments, Mater. Trans, 2007, 48(3), p 600–609

    Article  Google Scholar 

  19. N.H. Holroyd and G.M. Scamans, Stress Corrosion Cracking in Al-Zn-Mg-Cu Aluminium Alloys in Saline Environments, Metall. Mater. Trans. A, 2013, 44(March), p 1230–1253

    Article  Google Scholar 

  20. W. Gruhl, Stress Corrosion Cracking of High Strength Aluminium Alloys, Z. Metallkd., 1984, 75, p 819–826

    Google Scholar 

  21. M.B. Kannan and V.S. Raja, Enhancing Stress Corrosion Cracking Resistance in Al-Zn-Mg-Cu-Zr alloy through inhibiting recrystalization, Eng. Fract. Mech., 2010, 77(2), p 249–256

    Article  Google Scholar 

  22. Y. Deng, Z. Yin, K. Zhao, J. Duan, J. Hu, and Z. He, Effects of Sc and Zr Microalloying Additions and Ageing Time at 120°C on the Corrosion Behaviour of an Al-Zn-Mg Alloy, Corros. Sci., 2012, 65(December), p 288–299

    Article  Google Scholar 

  23. P.K. Rout, M.M. Ghosh, and K.S. Ghosh, Effect of Solution pH on Electrochemical and Stress Corrosion Cracking Behaviour of a 7150 Al-Zn-Mg-Cu Alloy, Mater. Sci. Eng. A, 2014, 604(May), p 156–165

    Article  Google Scholar 

  24. M. Czechowski, Effect of Anodic Polarization on Stress Corrosion Cracking of Some Aluminium Alloy, Adv. Mater. Sci., 2007, 7(1), p 13–20

    Google Scholar 

  25. A.E. Patterson, Introduction to Aluminium, Aluminium Federation of South Africa, Gauteng, 2007

    Google Scholar 

  26. K.S. Kumar, D. Singh, and T.B. Bhat, Studies on Aluminum Armour Plates Impacted by Deformable and Non-deformable Projectiles, Mater. Sci. Forum, 2004, 465–466, p 79–84

    Article  Google Scholar 

  27. C.G. Cordovilla, E. Louis, A. Pamies, L. Caballero, and M. Elices, Microstructure and Susceptibility to Stress Corrosion Cracking of Al-Zn-Mg Weldments (AA-7017), Mater. Sci. Eng. A, 1994, 174(2), p 173–186

    Article  Google Scholar 

  28. K.S.S. Eswar Raju, A.K. Mukhopadhayay, and S.V. Kamat, The Effect of Ageing on Tensile Behaviour, Mode I, and Mixed Mode I/III, Fracture Toughness of 7010 Aluminium Alloy, Int. J. Mater. Res., 2006, 97(11), p 1550–1558

    Article  Google Scholar 

  29. A.K. Mukhopadhyay, K.S. Prasad, V. Kumar, G.M. Reddy, S.V. Kamat, and V.K. Varma, Key Microstructural Features Responsible for Improved Stress Corrosion Cracking Resistance and Weldability in 7xxx Series Al Alloys Containing Micro/Trace Alloying Additions, Mater. Sci. Forum, 2006, 519–521, p 315–320

    Article  Google Scholar 

  30. C.G. Cordovilla, E. Louis, A. Pamies, L. Caballero, V. Sanchez-Galvez, and M. Elices, Stress Corrosion Susceptibility of Al-Zn-Mg Weldments: Microstructural Effects, Scr. Metall., 1989, 23(12), p 2091–2096

    Article  Google Scholar 

  31. J.C.F. Millette, N.K. Bourne, and M.R. Edwards, The Effect of Heat Treatment on the Shock Induced Mechanical Properties of the 7017 Aluminium Alloy, Scr. Mater., 2004, 51(10), p 967–971

    Article  Google Scholar 

  32. H. Möller and G. Govender, The Heat Treatment of Rheo-High Pressure Die Cast Al-Zn-Mg Alloy 7017, Solid State Phenom., 2013, 192–193, p 155–160J

    Google Scholar 

  33. Y. He, X. Zhang, and J. You, Effect of Minor Sc and Zr on Microstructure and Mechanical Properties of Al-Zn-Mg-Cu Alloy, Trans. Nonferrous Met. Soc. China, 2006, 16(5), p 1228–1235

    Article  Google Scholar 

  34. Z. Li, B. Xiong, Y. Zhang, B. Zhu, F. Wang, and H. Liu, Ageing Behaviour of an Al-Zn-Mg-Cu Alloy Pre-stretched Thick Plate, Material, 2007, 14(3), p 246–250

    Google Scholar 

  35. R.H. Brown and L.A. Willey, Constitution of Alloy, Aluminium, Vol 1, K.R. Van-Horn, Ed., ASM, Metal Park, 1967, p 31–54

    Google Scholar 

  36. A.K. Mukhopadhyay, C.N.J. Tite, H.M. Flower, P.J. Gregson, and F. Sale, Aluminium Lithium Alloys IV, Proceedings of the 4th International Conference on Aluminium Lithium Alloys, G. Champier, B. Dubost, D. Miannay and L. Sabetay, Paris, Ed., June, 1987 (Journal de Phyique, Suppl. 48), p C3:439.

  37. J.T. Jiang, W.Q. Xiao, L. Yang, W.Z. Shao, S.J. Yuan, and L. Zhen, Ageing Behaviour and Stress Corrosion Cracking Resistance of a Non-isothermally Aged Al-Zn-Ng-Cu Alloy, Mater. Sci. Eng. A, 2014, 605, p 167–175

    Article  Google Scholar 

  38. X. Fang, Y. Du, C. Jiang, M. Song, and K. Li, Effects of Cu Content on the Precipitation Process of Al-Zn-Mg Alloys, J. Mater. Sci., 2012, 47(23), p 8174–8187

    Article  Google Scholar 

  39. N. Birbilis and R.G. Buchheit, Investigation and Discussion of Characteristics for Intermetallic Phases Common to Aluminium Alloys as a Function of Solution pH, J. Electrochem. Soc., 2008, 155(3), p 117–126

    Article  Google Scholar 

  40. Y.L. Wua, U.F.H. Froesa, A. Alvareza, C.G. Lib, and J. Liuc, Microstructure and Properties of a New Super-High-Strength Al-Zn-Mg-Cu Alloy, C912, Mater. Des., 1997, 18(4–6), p 211–215

    Article  Google Scholar 

  41. H.C. Fang, K.H. Chen, X. Chen, H. Chao, and G.S. Peng, Effect of Cr, Yb and Zr Additions on Localized Corrosion of Al-Zn-Mg-Cu Alloy, Corros. Sci., 2009, 51(12), p 2872–2877

    Article  Google Scholar 

  42. S. Chen, K. Chen, P. Dong, S. Ye, and L. Huang, Effect of Recrystallization and Heat Treatment on Strength and SCC of an Al-Zn-Mg-Cu Alloy, J. Alloys Compd., 2013, 581(December), p 705–709

    Article  Google Scholar 

  43. G.S. Peng, K.H. Chen, H.C. Feng, Y.S. Chen, and H. Chao, The Effect of Recrystallization on Corrosion and Electrochemical Behaviour of 7150 Al Alloy, Mater. Corros., 2011, 62(1), p 35–40

    Article  Google Scholar 

  44. A.K. Jha, P.R. Narayanan, K. Sreekumar, and P.P. Sinha, Cracking of Al-4.5Zn-1.5Mg Aluminium Alloy Propellant Tank—A Metallurgical Investigation, Eng. Fail. Anal., 2010, 17(2), p 562–570

    Article  Google Scholar 

  45. R.H. Jones, ASM Handbook 13A. Corrosion: Fundamentals, Testing, and Protections, Metal Park, ASM, 2003, p 349–350

    Google Scholar 

Download references

Acknowledgments

The authors are very much thankful to the technical staff members of the Central Research Facility (CRF), and the IIT Kharagpur, India for allowing them to avail the facilities of SEM, TEM, and the hot and cold rolling mills as well.

Author information

Authors and Affiliations

  1. Department of Metallurgical and Materials Engineering, National Institute of Technology (NIT), Durgapur, India

    Prasanta Kumar Rout, M. M. Ghosh & K. S. Ghosh

Authors
  1. Prasanta Kumar Rout
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. M. M. Ghosh
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. K. S. Ghosh
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Prasanta Kumar Rout.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rout, P.K., Ghosh, M.M. & Ghosh, K.S. Influence of Aging Treatments on Alterations of Microstructural Features and Stress Corrosion Cracking Behavior of an Al-Zn-Mg Alloy. J. of Materi Eng and Perform 24, 2792–2805 (2015). https://doi.org/10.1007/s11665-015-1559-1

Download citation

  • Received:

  • Revised:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11665-015-1559-1

Keywords

Search

Navigation