Microstructural characterization and mechanical properties in friction stir welding of aluminum and titanium dissimilar alloys

Al–Si alloy and pure titanium were lap joined using friction stir welding technology. Microstructure and tensile properties of joints were examined. The maximum failure load of joints reached 62% of Al–Si alloy base metal with the joints fractured at the interface. X-ray diffraction results showed that new phase of TiAl3 formed at the interface. The microstructure evolution and the joining mechanism of aluminum–titanium joints were systematically discussed.