Microstructural characterization and mechanical properties of Al/Ti joint welded by CMT method—Assisted hybrid magnetic field

A novel external axial magnetic field (EMF) hybrid CMT welding-brazing process was adopted to join pure titanium TA2 and aluminum alloy 6061-T6. The effects of the magnetic intensity and frequency on microstructure and mechanical properties of the resultant joints were revealed. The experimental results indicated that the magnetic field can affect the flowability and surface spreadability of the molten filler metal on TA2 plate, thus forming the reliable Al/Ti joint. Grain refinement, decreased Al-Ti intermetallic compounds, and increased microhardness in both the heat-affected zone and the weld were observed with the applied of the EMF. The microstructure of the interfacial IMC layer was identified as TiAl3, and its thickness was decreased from 10 μm to 5 μm. In addition, the tensile shear strength of the Al/Ti joint reached a maximum value of 4.105 KN and fractured at the Ti base metal with the coil current and magnetic frequency set at 1.0 A and 10 Hz respectively, increasing by 93.4% compared to the normal welding process. However, the additional magnetic field could be an inverse effect on the process of Al/Ti dissimilar metal joining because of the unstable welding process.