Abstract
The microstructure and mechanical properties of friction spot welding (FSpW) 2198-T8 alloy during aging treatment were studied. Whereafter, the fracture process before and after aging treatment was observed by using the in-situ straining transmission electron microscopy method. The results show that fined equiaxed grains remained with predominant T1 phase re-precipitated in the microstrucuture of FSpW 2198-T8 Al-Li alloy after aging treatment. With the extension of holding time (12h–48h), grains gradually grew up in the range of 9.2–13.2μm and the size and volume fraction of T1 phases were also increased. Tensile strengths of thermal-mechanical coupling zone (TMCZ) of FSpW 2198-T8 alloy first increased and then decreased after aging treatment. When aging at 175°C for 36h, the strength reached the maximum (435MPa) with the elongation decreased to 11.4%. Meanwhile, the fracture mode of TMCZ zone transformed from ductile brittle mixed fracture to brittle fracture after aging treatment. And cracks initiated at and propagated along precipitate-free zones (PFZs) after aging treatment.
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 call
