Welding in the World

, Volume 62, Issue 4, pp 783–792 | Cite as

Exacerbated stress corrosion cracking in arc welds of 7xxx aluminum alloys

Henry Granjon prize 2017 winner Category B: Materials Behaviour and Weldability
  • T. E. Borchers
  • A. Seid
  • P. Shafer
  • W. Zhang
Research Paper


Cu-lean, high-strength 7xxx series aluminum alloys (AAs) are increasingly utilized in welded structures for vehicle light-weighting. The complex stress corrosion cracking (SCC) phenomenon in the 7xxx AA base metals has been extensively studied in the literature. However, the SCC in a welded joint is further compounded by the existence of highly inhomogeneous microstructure formed during welding. The present investigation is focused on the exacerbated SCC observed in the joints made of AA 7003-T4 (Al–Zn–Mg) plates welded with AA 5356 (Al–Mg) filler metal. It studies the contribution to SCC by a variety of factors especially the precipitates in the weld toe and the heat-affected zone in the as-welded and post-weld heat-treated conditions. The stress intensity factor experienced at the crack tip is ranked using the peak strain measured using the digital image correlation technique. Based on the testing results, a theory for the exacerbated SCC in the weld joints is established. Finally, the feasibility of two different engineering solutions to SCC in these weldments is discussed.


Aluminum alloys Arc welding Stress corrosion cracking Fused-overlap zone Transmission electron microscopy 



Aluminum alloy




Base metal


Digital image correlation


Electron discharge machining


Energy-dispersive x-ray spectroscopy


Filler metal


Fused-overlap zone


Fusion line


Friction stir welding


Fusion zone


Heat-affected zone


Intergranular corrosion


Stress intensity


Critical SCC stress intensity


Paint bake


Paint bake thermal cycle


Stress corrosion cracking


Stress corrosion cracking


Thermo-mechanically affected zone


Weld toe



The present research was supported by Honda R&D Americas, Inc. through the Manufacturing and Materials Joining Innovation Center (Ma2JIC), a NSF industry/university cooperative research center (I/UCRC). STEM was performed by Rachel Seibert of the Illinois Institute of Technology using the FEI Talos F200X STEM provided by the Department of Energy, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities. Helpful discussion with Dr. Niyanth Sridharan of Oak Ridge National Laboratory (ORNL) is acknowledged.


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Copyright information

© International Institute of Welding 2018

Authors and Affiliations

  1. 1.Department of Materials Science and EngineeringThe Ohio State UniversityColumbusUSA
  2. 2.Honda R&D Americas, Inc.RaymondUSA

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