Morphology, mechanical property, and molten pool dynamics by narrow gap AMF-GTAW with swing filler wire

The present study employed swing filler wire to enhance the microstructure and properties of thick joints in Ti–6Al–4V titanium alloy by narrow gap alternating-magnetic-field-assisted tungsten gas welding (AMF-GTAW). Results show that the addition of swing filler wire resulted in the refinement of prior β grains and α laths. Consequently, the tensile strength exhibited an increase from 877 ± 13 MPa to 913 ± 24 MPa (4.1% increase), while the fracture elongation showed a significant improvement from 6.3% ± 1.1% to 8.7% ± 0.9% (38.1% increase). The introduction of swing filler wire alters the flow state of the molten pool and exerts a stirring effect on its entirety. This stirring effect promotes nucleation and dendrite fragmentation within the molten pool.