• Lawal, Sunday A.
• Attah, Benjamin I.
• Abdulrahman, Asipita S.
• Medupin, Rasaq O.
• Akinlabi, Esther Titilayo
• Okoro, Uzoma G.
• Ipilakyaa, Tertsegha D.
• Sule, Gowon
• Adedipe, Oyewole
• Ikumapayi, Omolayo Michael
• Bala, Katsina C.

Abstract

<p>In this study, the friction stir welding (FSW) process was employed to investigate the effect of tool geometry on the corrosion behaviour and microstructure of friction stir welded AA7075-7651 and AA1200-H19 using Central Composite Design. The workpieces were machined and welded, and the interfaces were milled. A 2-level full factorial experimental design was deployed using Response Surface Methodology (RSM). A rotational speed of 1500 rpm, welding speed of 30, 60, and 90 mm/min, and a 2 tilt angle of the tool with a plunge force of 7 kN were utilized. The results show that regardless of the tool geometry, multi-response optimum weldment can be achieved at 60 mm/min welding speed and a tilt angle. The microstructure of the optimal weldments presents an 'onion ring'pattern, indicating proper mixing of the alloys during FSW. Analysis of the corrosion behaviour revealed a decrease in the polarization resistance when the transverse speed increased from 30 to 90 mm/min, as polarization resistance has a direct relationship with corrosion rate. It can be concluded that FSW ensures excellent weldment, as evident in the microstructural evolution of the resulting weldments, and that tool geometry plays a significant role in the corrosion inhibition efficiency of the alloys.</p>

Topics

• microstructure
• surface
• corrosion
• aluminium
• aluminium alloy
• composite