Microstructure and Mechanical Properties Correlation of FSAM Employed AA5083/AA7075 Joints

In the current study, the friction stir additive manufacturing (FSAM) technique was used to fabricate a three-layered build by using 3 mm thick sheets of AA5083 (top and bottom layer) and AA7075-T6 (middle layer) alloys. The effect of microstructure and texture evolution on the mechanical properties was studied comprehensively by using optical microscopy (OM), field emission scanning electron microscopy (FESEM), electron backscattered diffraction (EBSD), Vickers microhardness, and miniature tensile tests. Stir zones (SZ) along the build depth consist of fine equiaxed grains with complete intermixing of materials. The top and bottom region of the build shows appreciable strength and microhardness in comparison to BM (AA5083). The precipitate dissolution due to the multiple thermal cycles is the main contributing factor to decreased strength and microhardness in the middle region of the build. Microstructure gradients are observed owing to varying degrees of temperature gradient along the build depth. Texture analysis reveals the presence of ideal shear texture components A(1)*/A(2*,) B/B and C in the stir zones of the fabricated build, which suggests the presence of sufficient heat input during processing. The orientation distribution function (ODF) signifies the presence of recrystallization texture (Cube, P, and Goss) and plain strain texture (Brass and S) components in the SZ.