Improvement of tensile and impact properties of 5083 aluminium weldments using fillers containing nano-Al2O3and post-weld friction stir processing

Abstract

A new technique was used to improve the properties of 5083 aluminium weldments using nano-Al2O3. The single-pass welded metals were made using gas tungsten arc welding by fillers containing different amounts of nano-Al2O3particles fabricated using friction stir processing (FSP). To achieve a uniform distribution of nano-Al2O3particles, FSP was applied to the welding zone. In comparison with parts welded with conventional filler wires, a 29% increase in yield strength, 18% increase in tensile strength, and a 56% increase in impact energy were attained in the specimens welded using filler wires containing nano-Al2O3particles and post-weld FSP. The fracture mode of the weldments was changed from brittle (for the un-FSP'd specimens) to ductile (for the FSP'd specimens). Particles agglomeration, particle cracking, and weak matrix-reinforcement bonding reduce tensile properties. The impact fracture surface of the samples showed that the fracture mode of the FSP'd samples was ductile and the fracture was commonly initiated in the matrix. The uniform distribution of reinforcements leads to an improvement in the mechanical properties of the weldment.