Influence on the strength and aging resistance of aluminium joints by laser pre-treatment and surface modification

This paper describes the pre-treatment of the wrought aluminium alloy AW 6016, which is mainly employed in automotive car body manufacturing to reduce the weight. The major focus is on surface pre-treatment using laser to examine the influence of selected pre-treatment parameters on the strength and aging resistance of the bonded joint. The laser procedure presented is compared with surface pre-treatments on the basis of the wet-chemical deposition of a TiZr oxide layer and atmospheric pressure plasma (AP-plasma) treatment. The pre-treated surfaces were characterised using SEM-EDX, FTIR spectroscopy and XPS methods. Laser pre-treatment helped improve cleaning the surfaces and modify the oxide layer at the same time. The improvements resulted in better tensile shear strength of the bonded joint before and after aging.