Tensile and Fracture Properties of Aluminium Alloy AA2219-T87 Friction Stir Weld Joints for Aerospace Applications

Autor: M. Mohan, Bhanu Pant, Sushant K. Manwatkar, G. Sudarshan Rao, Dhenuvakonda Sivakumar, S. V. S. Narayana Murty, T. Antony Prabhu, P. Manikandan
Rok vydání: 2021
Předmět:
Zdroj: Metallurgical and Materials Transactions A. 52:3759-3776
ISSN: 1543-1940
1073-5623
Popis: The purpose of the present work is to study the mechanical behaviour of AA2219-T87 friction stir weld (FSW) joints at different temperatures (Room temperature (RT), 77 K and 20 K) and correlate them to the microstructures evolved during the joining process. For this purpose, standard full length tensile specimens as well as miniature tensile specimens extracted from different microstructural regions of the joint such as weld nugget zone (WNZ), thermo-mechanically affected zone (TMAZ) and heat-affected zone were used. Similarly, fracture toughness (FT) was evaluated by placing notches at the three microstructurally different regions. The tensile properties at 77 K and 20 K were higher compared to those at room temperature. Miniature tensile specimens extracted from WNZ and TMAZ regions showed similar strength properties; however lower hardness and ductility were observed in TMAZ. Failure of standard full length samples was always in TMAZ since it has lower hardness and ductility, as a result of strain hardening. The higher FT noticed in WNZ is attributed to the presence of very fine grains. The lower FT observed in the TMAZ is attributed to combined effect of the absence of strengthening precipitates and recrystallization. Comparison of the mechanical properties of AA2219-T87 FSW and TIG weld joints revealed superior tensile properties at room and cryogenic temperatures for FSW weld joints, thus making FSW, a better alternative for the fabrication of large sized earth storable and cryogenic propellant tanks of satellite launch vehicles.
Databáze: OpenAIRE
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