Dissimilar Electron Beam Welding of Iron and Nickel Alloy Systems

Electron beam welding (EBW) processes have a high absorptivity with metals and a small spot size which enables the precise control of the width and depth of the narrow weld pools. Advanced controls in EBW systems include beam deflection which can be used to control the fluid flow and keyhole position in the weld pool. These unique capabilities enable the precise control of the weld pool location and composition in dissimilar metal joints. This study investigated how the location of an oscillating electron beam affected the solidification structures in dissimilar iron-nickel welds. Butt welds were fabricated with the electron beam focusing on the nickel transitioning to focusing on the iron so that a range of composition gradients could be analyzed. The structures that formed at the fusion boundaries as the composition of the fusion zone changed was of particular interest to this work.