Abstract

KIANEZHAD, M.  and  HONARBAKHSH RAOUF, A.. Improvement of tensile and impact properties of 5083 aluminium weldments using fillers containing nano-Al₂O₃ and post-weld friction stir processing. J. S. Afr. Inst. Min. Metall. [online]. 2020, vol.120, n.4, pp.277-286. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/662/2020.

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-Al₂O₃ particles fabricated using friction stir processing (FSP). To achieve a uniform distribution of nano-Al₂O₃ particles, 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-Al₂O₃ particles 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.

Keywords : gas tungsten arc welding; filler metal fabrication; friction stir processing; 5083 aluminium alloy; impact energy; tensile fracture.

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