Mechanical properties and microstructures of FSW joint of C24S-T8 Al-Li alloy were investigated.
The strength coefficient of the joint welded with optimized technical parameters reached 82%. During the tensile
process, plastic deformation and fracture were concentrated in the weld. The nugget zone possessed fine recrystallized
equiaxed grains with an average size of about 2. 3 mm, most grain boundaries were of high angle larger than 15 °. The
grains of the thermomechanically affected zone underwent deflection and deformation during the welding process. The
strengthening precipitates of C24S-T8 Al-Li alloy consisted of T1(Al2CuLi), θ′(Al2Cu) and S′(Al2CuMg). In the
thermomechanically affected zone and nugget zone, these precipitates were completely dissolved, leading to the decrease
in hardness.