Molten pool morphology and microstructure evolution of WAAM Ti6Al4V under in-situ electropulsing

When the pulsed current is used to assist the WAAM process, the entire working area is in an external magnetic field due to electromagnetic coupling. The stable arc is deflected by the Lorentz force, which stirs the molten pool and accelerates the fluidity of the melt. Through the high-speed camera recording process, it could be found that the larger pulsed parameter EPT-2 had a stronger deflection angle than EPT-1. However, the stirring effect was weakened due to the arc deflection out of the molten pool. When the current was reversely connected (EPT-2(R)), the arc was subjected to a reverse deflection force, and the early melting of the filler wire caused the current intensity to decrease. Furthermore, the reversal of the electrode position (EPT-2(SR)) on the substrate also changed the current flow path and woke the effect of the current. Finally, combined with SEM and hardness results, the regulation effect of pulsed current on microstructure and properties: EPT-1 > EPT-2 > EPT-2(R) > EPT-2(SR).