Effect of primer and sealant in refill friction stir spot welded joints on strength and fatigue behaviour of aluminium alloys
Petr Homola, Roman Růžek, Anthony R. McAndrew, Jeroen De Backer
Abstract
The refill friction stir spot welding (RFSSW) is one of the promising friction stir welding (FSW) methods consisting in the joint creation by plunging and retracting the rotating tool into the overlapped sheets without an exit hole after welding. This work aims to fulfil a knowledge gap related to use of aluminium semi-products in a final configuration state (including anodizing, primer and sealant application) for RFSSW process by means of the lap-shear and cross-tension mechanical test, fatigue performance, metallographic and fractographic analyses, and digital image correlation (DIC) technique. Sheet semi-products of thicknesses from 2 to 3 mm made of AA7050-T7451 and AA2024-T3 aluminium alloys in bare and/or anodised condition were used for the lap-joint specimens manufacturing and five various material joint combinations were analysed. The effect on static strength for the joint configurations with primer and sealant was studied and compared with the bare materials’ RFSSW joints. Fatigue tests showed that the primed configurations exhibited a higher scatter of the results and a different slope of fatigue curve with a higher fatigue limit value as compared with the bare material’s joints exhibiting a higher ultimate static strength.