Advertisement

Journal of Failure Analysis and Prevention

, Volume 16, Issue 6, pp 1141–1149 | Cite as

Metallurgical Analysis of Cracked AA7075 Aluminum Alloy Component Used in Control System of a Satellite Launch Vehicle

  • Sushant K. Manwatkar
  • J. Srinath
  • S. V. S. Narayana Murty
  • P. Ramesh Narayanan
  • S. C. Sharma
  • P. V. Venkitakrishnan
Technical Article---Peer-Reviewed
  • 124 Downloads

Abstract

High-strength aluminum alloy AA7075 forgings are widely used in various control system components of liquid engines of satellite launch vehicles. In one such application, a forged component was found to crack under storage. Multiple cracks were noticed on the surface of the component. Fractographic features indicated intergranular mode of failure. Optical microscopic examination revealed dendritic coring in the material and crack propagation to be along the grain boundaries. Anodic dissolution of grain boundaries was also noticed. Based on detailed metallurgical investigations, it was concluded that the failure was due to ‘stress corrosion cracking.’

Keywords

AA7075 alloy Intergranular cracking Dendritic Coring Stress corrosion cracking 

Notes

Acknowledgment

The authors are thankful to Director VSSC for his kind permission to publish this work. They further wish to thank Director LPSC Valiamala for referring the analysis and for supplying the specimens.

References

  1. 1.
    R.F. Muraca, J.S. Whittick, Materials data handbook- Aluminium Alloy 7075, 2nd edn. (Western applied research and development Inc, California, 1972)Google Scholar
  2. 2.
    S.D. Cramer, B.S. Bernard Jr., Corrosion: Fundamentals, Testing and protection, ASM Handbook, vol. 13A (ASM International, Materials Park, 2003)Google Scholar
  3. 3.
    E. John, Hatch, Aluminum, Properties and Physical Metallurgy (American Society for Metals, Ohio, 1984)Google Scholar
  4. 4.
    V.S. Raja, T. Shoji, Stress Corrosion Cracking: Theory and Practise (Woodhead Publishing Ltd, Cambridge, 2011)CrossRefGoogle Scholar
  5. 5.
    M.O. Speidel, Stress Corrosion Cracking of Aluminum Alloys. Metall. Trans. A 6, 631–651 (1975)CrossRefGoogle Scholar
  6. 6.
    T.D. Burleigh, The postulated mechanisms for stress corrosion cracking of aluminum alloys- a review of the literature 1980–1989. Corrosion 49, 89–98 (1991)CrossRefGoogle Scholar
  7. 7.
    A.F. Oliveira Jr., M.C. De Barros, K.R. Cardoso, D.N. Travessa, The effect of RRA on the strength and SCC resistance on AA7050 and AA7150 aluminum alloys. Mater. Sci. Eng. A 379(1–2), 321–326 (2004)CrossRefGoogle Scholar
  8. 8.
    R. Ghosh, A. Venugopal, P. Sankaravelayudham, R. Panda, S.C. Sharma, K.M. George, V.S. Raja, Effect of thermomechanical treatment on the environmentally induced cracking behavior of AA7075 alloy. J. Mater. Eng. Perform. 24(2), 545–555 (2015)CrossRefGoogle Scholar
  9. 9.
    D.S. Mackenzie, G.E. Totten, Analytical Characterization of Aluminium, Steel and Superalloys (Taylor & Francis, London, 2006)Google Scholar

Copyright information

© ASM International 2016

Authors and Affiliations

  • Sushant K. Manwatkar
    • 1
  • J. Srinath
    • 1
  • S. V. S. Narayana Murty
    • 1
  • P. Ramesh Narayanan
    • 1
  • S. C. Sharma
    • 1
  • P. V. Venkitakrishnan
    • 1
  1. 1.Materials and Mechanical EntityVikram Sarabhai Space CentreTrivandrumIndia

Personalised recommendations