Joining mechanism of Ti/Al dissimilar alloys during laser welding-brazing process

▶ The microstructures of interfacial zones were confirmed in detail by transmission electron microscope (TEM). Interfacial reaction layers of brazing joint were composed of α-Ti, nanosize granular Ti7Al5Si12 and serration-shaped TiAl3. For the first time, obvious stacking fault structure in intermetallic phase TiAl3 was found when the thickness of the reaction layer was very thin (approximately below 1 μm). ▶ Metallurgical characteristics for laser welding-brazing process in the environment of far from equilibrium was expounded by microstructures of the joints, the characteristics of thermal process and element diffusion behavior.