Effect of beam oscillation on porosity and intermetallics of electron beam welded DP600-steel to Al 5754-alloy

Abstract

Formation of porosity and intermetallic compounds (IMCs) were studied in electron beam welded (EBW) DP-600 steel to Al-5754 alloy joints at three different weld conditions such as without beam oscillation, with beam oscillation and with varying beam oscillation diameter. X-ray Diffraction (XRD), scanning electron microscopy (SEM), microhardness, three-dimensional X-ray computed tomography (XCT) were used to characterize porosity and IMCs distribution in these weld joints. Beam oscillation with optimum oscillation diameter (1 mm diameter) improved the weld quality by reducing the amount, maximum size and porosity contents in weld zone significantly. For IMCs, average size increased little bit but maximum size, percentage of formation and amount reduced. By increasing oscillation diameter (2 mm diameter) beyond optimum value (1 mm diameter), quality of joints was found to deteriorate with accompanying higher porosity content, average pore size, average IMCs size etc. Raman spectroscopy and gas analyzer were also used to identify and quantify the entrapped gases in the weld joint.