Effect of External Magnetic Field on the Microstructure of 316L Stainless Steel Fabricated by Directed Energy Deposition

Abstract

Abstract Directed energy deposition (DED) is a major additive manufacturing (AM) process, which employs high energy beams as the heat source to melt and deposit metal powder in a layer-by-layer fashion such that complex components can be manufactured. In this study, a magnetic-field-assisted DED method is applied to control the microstructure and element distribution in the deposited materials. For this purpose, to control the microstructure of DED-built 316L stainless steel, a horizontal magnetic field is introduced during the DED process at different levels of magnetic field intensities (i.e., 0T, 1.0T and 1.8T). Scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS) are used to characterize the microstructure of components obtained with different magnetic field strengths. The results show that the microstructure of deposited materials is significantly affected by the external magnetic field. Also, the result of interdendritic microsegregation pattern presents a transformation from continuous morphology to discrete morphology because of the applied magnetic field. Along with the increasing horizontal magnetic field intensity, nickel and chromium content are changed significantly in austenite and ferrite.