Microstructure and texture characterization in friction stir lap welded TIMETAL 21S

The evolution of microstructure and texture during friction stir lap welding (FSLW) TIMETAL 21S (β-type Ti-15Mo-3Nb-3Al-0.2Si, wt%) sheets were investigated through electron backscatter diffraction (EBSD). Excellent grain refinement is obtained zone (SZ) thickness (1.2–1.8 μm). the thermomechanically affected (TMAZ) characterized by elongated deformed grains surrounded small recrystallized indicating occurrence discontinuous dynamic recrystallization (DDRX). heat (HAZ) quite similar to base metal (BM). transformed from weak rolling-recrystallization in BM HAZ a typical shear with domination D1 or D2 components SZ TMAZ area. A net gradient formed across which connected heterogeneity deformation. It believed that concomitant size, dislocation strengthening responsible for mechanical property distribution different parts FSLW joint.