Structure-property correlation of weld metal zone and interface regions of cold metal transfer welded dissimilar Al-Mg-Mn alloys joint

Abstract

Cold Metal Transfer (CMT) welding of dissimilar Al-2.6 Mg-0.5Mn (A5754) and Al-4.5 Mg-1.0Mn (A5083) aluminium alloys has been performed with ER5356 filler wire. The microstructure and mechanical properties of the weld-metal zone (WMZ) and interface regions are correlated. The microstructure reveals epitaxial grains at the edge of the partially molten zone (PMZ) and equiaxed dendritic structure at the center of the WMZ. Energy dispersive spectroscopy (EDS) results show that the WMZ and PMZs are composed of α-Al, Al<inf>3</inf>Mg<inf>2</inf>and Al<inf>6</inf>Mn phases. The WMZ exhibits higher hardness and strength due to the existence of equiaxed dendrite structure, dilution effect and absence of defects. The interface region of A5083 side exhibits higher hardness and strength due to the presence of finer grains and higher volume fine secondary phases in the PMZ and HAZ of this side than at the other side. Fracture surface of all the samples exhibits dimples indicating a ductile fracture. © 2021 Elsevier Ltd. All rights reserved.