Influence of the kissing bond defect on the fatigue life in friction stir welds of 2024 aluminium alloy

Article information

Abstract

Static and fatigue experiments were performed on friction stir (FS) welds in 2024-T3 aluminium alloys to investigate the influence of kissing bond (KB) flaws on the static strength and fatigue life of the FS welds. Different categories of FS welded plates were manufactured: a flaw-free plate and FS welded plates with different levels of KB size. The effects of the KB flaws on tensile and fatigue properties of AA2024-T3 specimens extracted from the plates were quantitatively evaluated with respect to the flaw-free weld. The various levels of KB flaw size were investigated with the aim of determining a flaw size that does not affect the fatigue life of the joined 6.35-mm-thick plates. The critical value for the KB geometry seems to be below 400 μm in depth based on the influence on the fatigue life for the investigated categories. The fatigue life of welds with KB flaws of 615 μm average depth was approximately seven times shorter than for flaw-free welds. The test results were supported by metallographic analyses and provide a baseline for definition of the flaw detection requirements related the sensitivity of non-destructive equipment.

Keywords:

fatigue strength

friction stir welding

kissing bond

2024 aluminium alloy

aerospace vehicles.

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