Abstract
In this study, the 1.8mm thick cold-rolled sheets of 2198-T8 Al–Li alloy were manufactured by friction stir welding (FSW) at a rotation rate of 800rpm and a travel speed of 300mm/min. The microstructure and mechanical properties of different regions of the produced joint were evaluated by means of optical microscopy (OM), transmission electron microscopy (TEM), hardness testing and tensile testing. Results show that the original “pancake” grains became coarser in the heat affected zone (HAZ), transformed into equiaxed grains in the stir shoulder zone (SsZ) and stir pin zone (SpZ), and formed mixed grains with both “pancake” and equiaxed shapes in the thermo-mechanical affected zone (TMAZ). The hardness distribution in the cross-section of the FSW joint exhibited a “basin” shape. When approaching the weld centre, the hardness gradually decreased compared to the base metal (BM). The BM exhibited the highest strength due to the presence of fine T1 phase. In the HAZ, the strength decreased as T1 phase was partially dissolved. In the SsZ and SpZ, in spite of strength contribution from grain refinement, the strength further decreased as T1 phase was fully dissolved. The minimum strength in the TMAZ was related to the reduced amount of T1 phase and the presence of transition layer with sharp gradient of grain size.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
