Influence mechanisms of Y-direction magnetic field-assisted laser penetration welding on the molten pool behavior and joint characteristics of layered DSS2205/X65 bimetallic composite

Abstract

Under the influence of the Y-direction magnetic field, the weld profile was significantly altered, with a reduction in the transition zone dimensions and joint inhomogeneity. The weld exhibited a refined microstructure, with the transition zone closely aligned along the original explosion-welded interface. The influence of the magnetic field became significant when the Y-direction magnetic flux density ranged from 100 mT to 180 mT. The austenite content in the compound layered zone increased from 11 % to 35 % even more. The joint achieved an optimal balance among transition zone size, joint uniformity, austenite content and corrosion resistance at 100 mT. Magnetic fields affect melting and solidification behavior through mechanisms, including plasma flexure and dilution, electromagnetic forces generated by induced currents, and thermoelectric forces arising from thermal gradients. The Y-direction magnetic field optimized the laser-welded joint by diluting the plasma, enhancing laser energy utilization, and accelerating the solidification rate at the molten pool center. The redistribution of austenite and ferrite phases and increased austenite content improved the corrosion resistance of the joint. This work provides a strategy for optimizing molten pool behavior and weld structure in laser welding of layered materials using magnetic fields, offering significant value for the design, development, and manufacturing of layered metallic composites.