Influence of AC-TIG weld current on dissimilar AA5083 and AA 7075 aluminium alloy

ABSTRACT

Dissimilar weld made of AA5083 and AA 7075 aluminium alloys using TIG welding (Current inthe range of 80120 amps) has investigated. Ultimate tensile strength of different weld joints fabricated at different current considered for assessing the joint quality. The results demonstrated that an optimum weld current of 100 amp yielded ~ 283 MPa tensile strength. Compositional analysis across weld pool has shown a signature of Mg vaporisation and Zn retention resulting in yielding high weld strength. The dilution curves of the Zn in 7075 side of TIG welded specimens show a gradual decrease in Zn fraction in HAZ leads to failure of tested samples along the HAZ side of AA7075. It has found that in the weld microstructure,there is a tendency in the weld zone for stabilising Mg by forming various intermetallic phases.

KEYWORDS:

• Fusion welding
• columnar grain
• hardness
• dimples
• mixed mode of fracture

Acknowledgments

Authors would like to express a deep sense of gratitude to Dr. K.V.L. Raju, Principal, MVGR College of Engineering (A) and Dr Kaustav Bharat, National Aerospace Bangalore for his valuable inputs.

Disclosure statement

No potential conflict of interest was reported by the author(s).