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Effect of the interrupted aging heat treatment T6I4 on the tensile properties and fatigue resistance of AA7050 alloy

  • A. M. B. S. Antunes
  • C. A. R. P. BaptistaEmail author
  • M. J. R. Barboza
  • A. L. M. Carvalho
  • N. V. V. Mogili
Technical Paper

Abstract

The tensile response and the fatigue behavior of age-hardenable aluminum alloys are strongly influenced by factors like the size, spacing and volume fraction of strengthening precipitates. Previous researches have shown that the interrupted aging (T6I4) could provide an improved combination of mechanical properties for some alloys. In this study, the tensile properties and high-cycle fatigue behavior of two tempers of AA7050 alloy (the commercial T7451 and the interrupted aging T6I4) were investigated. Transmission electron microscopy analyses of strengthening precipitates were performed, and the results showed that AA7050-T6I4 had a higher volume fraction of strengthening precipitates with smaller size. This microstructural feature was responsible by the higher ductility and toughness shown by T6I4 temper condition while maintaining yield stress and ultimate tensile strength similar to T7451. The smooth samples rotating bending fatigue curves of both material conditions were similar. Nevertheless, the interrupted aging leads to improved notched fatigue resistance and hence lower notch sensitivity. These results were related to the higher activity of screw dislocations and improved dislocation pinning effect during deformation promoted by T6I4 temper.

Keywords

Aluminum alloys Age hardening Mechanical characterization Fatigue 

Notes

Acknowledgements

The research was financially supported by CNPq—National Council for Scientific and Technological Development and CAPES—Coordination for the Improvement of Higher Education Personnel. Research supported by LNNano—Brazilian Nanotechnology National Laboratory, CNPEM—Brazilian Center for Research in Energy and Materials /MCTI—Ministry of Science, Technology and Innovation.

References

  1. 1.
    Buha J, Lumley RN, Crosky AG (2008) Secondary ageing in an aluminum alloy 7050. Mater Sci Eng, A 492:1–10CrossRefGoogle Scholar
  2. 2.
    Bai Q, Li H, Du Q, Zhang J, Zhuang L (2016) Mechanical properties and constitutive behaviors of as-cast 7050 aluminum alloy from room temperature to above the solidus temperature. Int J Miner Metall Mater 23:949–958CrossRefGoogle Scholar
  3. 3.
    Buha J, Lumley RN, Crosky AG, Hono K (2007) Secondary precipitation in an Al–Mg–Si–Cu alloy. Acta Mater 55:3015–3024CrossRefGoogle Scholar
  4. 4.
    Jiang F, Zurob HS, Purdy GR, Zhang H (2016) Characterizing precipitate evolution of an Al–Zn–Mg–Cu based commercial alloy during artificial aging and non-isothermal heat treatments by in situ electrical resistivity monitoring. Mater Charact 117:47–56CrossRefGoogle Scholar
  5. 5.
    Du ZW, Sun ZM, Shao BL, Zhou TT, Chen CQ (2006) Quantitative evaluation of precipitates in an Al–Zn–Mg–Cu alloy after isothermal aging. Mater Charact 56:121–128CrossRefGoogle Scholar
  6. 6.
    Yang W, Ji S, Zhang Q, Wang M (2015) Investigation of mechanical and corrosion properties of an Al–Zn–Mg–Cu alloy under various ageing conditions and interface analysis of η′ precipitate. Mater Des 85:752–761CrossRefGoogle Scholar
  7. 7.
    Lin J, Liao H, Jehng W, Chang C, Lee S (2006) Effect of heat treatments on the tensile strength and SCC-resistance of AA7050 in an alkaline saline solution. Corros Sci 48:3139–3156CrossRefGoogle Scholar
  8. 8.
    Chen J, Zhen L, Yang S, Shao W, Dai S (2009) Investigation of precipitation behavior and related hardening in AA 7055 aluminum alloy. Mater Sci Eng, A 500:34–42CrossRefGoogle Scholar
  9. 9.
    Magalhães DCC, Hupalo MF, Cintho OM (2014) Natural aging behavior of AA7050 Al alloy after cryogenic rolling. Mater Sci Eng, A 593:1–7CrossRefGoogle Scholar
  10. 10.
    Chen Y, Weyland M, Hutchinson CR (2013) The effect of interrupted aging on the yield strength and uniform elongation of precipitation-hardened Al alloys. Acta Mater 61:5877–5894CrossRefGoogle Scholar
  11. 11.
    Marceau RKW, Sha G, Lumley RN, Ringer SP (2010) Evolution of solute clustering in Al–Cu–Mg alloys during secondary ageing. Acta Mater 58:1795–1805CrossRefGoogle Scholar
  12. 12.
    Lumley RN, Polmear IJ, Morton AJ (2002) Control of secondary precipitation to improve the performance of aluminium alloys. Mater Sci Forum 396–402:893–898CrossRefGoogle Scholar
  13. 13.
    Lumley RN, Polmear IJ, Morton AJ (2004) Temper developments using secondary ageing. Mater Forum 28:85–95Google Scholar
  14. 14.
    Weixing Y, Kaiquan X, Yi G (1995) On the fatigue notch factor. Kf Int J Fatigue 17:245–251CrossRefGoogle Scholar
  15. 15.
    ASTM E8/E8 M-11 (2011) Standard test methods for tension testing of metallic materialsGoogle Scholar
  16. 16.
    Castro JTP, Meggiolaro MA (2009) Fatigue: Technical and structural design practices under real loads of service, 1st edn. CreateSpace, Scotts ValleyGoogle Scholar
  17. 17.
    ASTM E739-10 (2010) Standard practice for statistical analysis of linear or linearized stress-life (S–N) and strain-life (ε-N) fatigue dataGoogle Scholar
  18. 18.
    Birbilis N, Cavanaugh MK, Buchheit RG (2006) Electrochemical behavior and localized corrosion associated with Al7Cu2Fe particles in aluminum alloy 7075-T651. Corros Sci 48:4202–4215CrossRefGoogle Scholar
  19. 19.
    Chemin A, Marques D, Bisanha L, Motheo AJ, Filho WWB, Ruchert COF (2014) Influence of Al7Cu2Fe intermetallic particles on the localized corrosion of high strength aluminum alloys. Mater Des 53:118–123CrossRefGoogle Scholar
  20. 20.
    Lima LOR, Jacumasso SC, Ruchert COFT, Martins JP, Carvalho ALM (2014) Study of the effects of two-step ageing heat treatment on fatigue crack growth on an AA7050 aluminum alloy. Adv Mater Res 891–892:1111–1116CrossRefGoogle Scholar
  21. 21.
    Wang YL, Pan QL, Wei LL, Li B, Wang Y (2014) Effect of retrogression and reaging treatment on the microstructure and fatigue crack growth behavior of 7050 aluminum alloy thick plate. Mater Des 55:857–863CrossRefGoogle Scholar
  22. 22.
    Hertzberg RW (1996) Deformation and fracture mechanics of engineering materials, 4th edn. Wiley, New YorkGoogle Scholar
  23. 23.
    Kleemola HJ, Nieminen MA (1974) On the strain-hardening parameters of metals. Metall Trans 5:1863–1866CrossRefGoogle Scholar
  24. 24.
    Tahreen N, Chen DL, Nouri M, Li DY (2014) Effects of aluminum content and strain rate on strain hardening behavior of cast magnesium alloys during compression. Mater Sci Eng, A 594:235–245CrossRefGoogle Scholar
  25. 25.
    Mondal C, Singh AK, Mukhopadhyay AK, Chattopadhyay K (2013) Tensile flow and work hardening behavior of hot cross-rolled AA7010 aluminum alloy sheets. Mater Sci Eng, A 577:87–100CrossRefGoogle Scholar
  26. 26.
    Gao YK (2011) Improvement of fatigue property in 7050-T7451 aluminum alloy by laser peening and shot peening. Mater Sci Eng, A 528:3823–3828CrossRefGoogle Scholar
  27. 27.
    Liu R, Zhang ZJ, Zhang ZF (2016) The criteria for microstructure evolution of Cu and Cu–Al alloys induced by cyclic loading. Mater Sci Eng, A 666:123–138CrossRefGoogle Scholar
  28. 28.
    Ma K, Hu T, Yang H, Topping T, Yousefiani A, Lavernia EJ, Schoenung JM (2016) Coupling of dislocations and precipitates: impact on the mechanical behavior of ultrafine grained Al–Zn–Mg alloys. Acta Mater 103:153–164CrossRefGoogle Scholar
  29. 29.
    Li J (2007) The effect of microstructure and texture on high cycle fatigue properties of Al alloys. PhD. thesis, University of KentuckyGoogle Scholar
  30. 30.
    Xiao-song J, Guo-qiu H, Bing L, Song-jie F, Min-hao Z (2011) Microstructure-based analysis of fatigue behaviour of Al–Si–Mg alloy. Trans Nonferrous Met Soc China 21:443–448CrossRefGoogle Scholar
  31. 31.
    Orowan E (1948) Symposium on internal stress in metals and alloys. Institute of Metals, LondonGoogle Scholar
  32. 32.
    Bennett JA, Weinberg JG (1954) Fatigue notch sensitivity of some aluminum alloys. J Res Natl Bur Stand 52:235–245CrossRefGoogle Scholar
  33. 33.
    Wei L, Pan Q, Wang Y, Feng L, Huang H (2013) Characterization of fracture and fatigue behavior of 7050 aluminum alloy ultra-thick plate. J Mater Eng Perform 22:2665–2672CrossRefGoogle Scholar
  34. 34.
    Gupta VK, Agnew SR (2011) Fatigue crack surface crystallography near crack initiating particle clusters in precipitation hardened legacy and modern Al–Zn–Mg–Cu alloys. Int J Fatigue 33:1159–1174CrossRefGoogle Scholar
  35. 35.
    Payne J, Welsh G, Christ RJ, Nardiello J, Papazian JM (2010) Observations of fatigue crack initiation in 7075-T651. Int J Fatigue 32:247–255CrossRefGoogle Scholar
  36. 36.
    Xue Y, Kadiri HE, Horstemeyer MF, Jordon JB, Weiland H (2007) Micromechanisms of multistage fatigue crack growth in a high-strength aluminum alloy. Acta Mater 55:1975–1984CrossRefGoogle Scholar

Copyright information

© The Brazilian Society of Mechanical Sciences and Engineering 2019

Authors and Affiliations

  1. 1.Engineering School of Lorena, EEL-USPUniversity of São PauloLorenaBrazil
  2. 2.State University of Ponta Grossa - UEPGPonta GrossaBrazil
  3. 3.National Center for Research in Energy and Materials (CNPEM)CampinasBrazil

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