Effect of magnetic Field on the microstructure and mechanical properties of inconel 625 superalloy fabricated by wire arc additive manufacturing

Abstract

• The magnetic field has been applied during the Wire Arc Additive Manufacturing (WAAM) processing of Inconel 625 . • The mechanism that the effect generated by magnetic field on the microstructure was discussed. • The application of magnetic fieldeffectively improves the mechanical properties of WAAM Inconel 625 alloy. Wire Arc Additive Manufacturing (WAAM) technology for Inconel 625 alloy is increasingly being considered for its high deposition efficiency, low cost and flexible manufacturing capability. However, very high heat input and severe elemental segregation during additive manufacturing process reduces the forming quality of Inconel 625 alloy and degrades its performance. In this work, magnetic field has been applied during the Cold Metal Transfer (CMT) WAAM processing of Inconel 625 to modify its microstructure. The effect of the magnetic field applied during the CMT-WAAM process on the microstructure and mechanical properties of Inconel 625 alloy has been studied. Results show that: (i) the stirring effect of the magnetic field during the deposition process refines dendritic crystal size and (ii) the convection generated by the magnetic field promotes diffusion of elements such as Nb and Mo in the melt pool, thereby inhibiting segregation. Evaluation of the mechanical properties of the Inconel 625 alloy deposited under magnetic field shows an increase in its hardness, yield strength (∼13 %), ultimate tensile strength (UTS) and elongation. From the work, it is evident that the application of magnetic field during CMT-WAAM process, refines the dendritic crystals, suppresses segregation, and effectively improves the mechanical properties of Inconel 625 alloy.