LAUSR

Abstract Copper-stainless steel joints are achieved with sound double-sided appearances using Cu-based, Cu-Ni-based and Fe-based filler metals. The weld zone in the Cu-based filled joint consists of a uniform structure with the Cu solid solution (s,s) phase. The mixture of immiscible Cu and Fe causes weld segregation to appear in the other two joints. The weld zones with mixed phases in the Cu-Ni-based and Fe-based filled joints show higher impact toughness than the weld zone in the Cu-based filled joint. The maximum tensile strength is obtained from the Cu-based filled joint, which can reach up to 80 % of copper tensile strength. The decreased dislocation density and grain-coarsening under the annealing effect softens the heat-affected zone (HAZ) on the copper side of all three joints, making them a fracture zone during tensile tests. All the joints fracture with a ductile mode, and the plastic deformation concentrates on the softened copper side. The Cu-based filled joint exhibits the highest plastic deformation, which is primarily caused by the large deformation of the weld zone and the large deformation of the Cu base metal caused by the high plasticity of the weld that alleviates the stress concentration.