The microstructure and properties evolution of SS316L fabricated by magnetic field-assisted laser powder bed fusion

Magnetic field-assisted laser-based additive manufacturing provides a feasible method for the fabrication and performance improvement of metal parts. In this research, the effects of axial static and alternating magnetic field-assisted laser powder bed fusion on mechanical properties and microstructure of stainless steel 316L are investigated. Under static magnetic field, the epitaxial growth and <001> crystallographic texture along the building direction are inhibited and cellular dendrites are deflected from the solidification direction by thermoelectric magnetic force. With increasing relative density and <110> texture, the ductility of specimens increases significantly and reaches 52.6%. When an alternating magnetic field is applied, the long epitaxial cellular dendrites along the heat dissipation route and cell spacing decrease. The epitaxial growth along the building direction is significantly blocked by the interaction of induced current and magnetic field. The preferred orientation of crystals is also changed, indicating a strong <102> crystallographic texture along the building direction. In addition, the strength and ductility of specimens are improved under an alternating magnetic field.