Microstructure and Fracturing Behavior of AA7075–T651 Aluminum Alloy Cooled During Friction Stir Welding
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Friction-stir-welded joints of 16-mm-thick plates of AA7075 aluminum alloy have been studied. The macrostructure of the weld region over the thickness of the plates and microstructures of various regions of the welded joint were determined using optical and transmission electron microscopes. Tensile testing of the welded samples was conducted, and the average values of the ultimate strength and yield point, as well as relative elongation were calculated. The Vickers hardness profiles in the middle of the cross-section of the welded joint were measured. Friction stir welding with forced cooling (by a compressed air flow or water immersion) was tested to reduce heat damage and improve mechanical properties. The efficiency of such welding has been demonstrated.
Key wordsAA7075 aluminum alloy friction stir welding forced cooling fracturing transmission electron microscopy
The authors acknowledge the financial support from the Armament Research Board, DRDO, Ministry of Defence, India, through an R&D project No. ARMREB/MAA/2012/142. The authors acknowledge the support provided by the DMRL, Hyderabad, for conducting friction stir welding trails. The authors would like to thank Dr. M. Selvaraj, Associate Professor, SSN College of Engineering, Chennai, for his help in computing the thermal cycles.
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