Influence of Process-Related Defects on the Fatigue Behaviour of Welded Aluminium Joints at Very High Cycles

Abstract:

The influence of geometrical notch and weld defects (pores and incomplete fusions) on the fatigue behaviour at very high numbers of loading cycles is shown for welded samples made of the base material EN AW-5083 and EN AW-6082 and the filler material S Al 5183. High frequency fatigue tests with specimens highest stressed cross-sections representing different welding zones show no endurance limit up to 2·10⁹ load cycles. The weakest link of the weld seams are the geometrical notch and (if present) pores and incomplete fusions in the seam interior and at the surface. Considering weld defects in the filler material as fatigue crack initiating notches, a threshold value for the cyclic stress intensity factor (ΔK_min) of 0.9 MPam was found. Using ΔK_min the fatigue life of the samples is discussed on the basis of stress amplitude, the projected area of the defect and its position. X-ray examinations revealed a good correlation between the failure-relevant defect areas and the overall fatigue life of welded samples.

• Periodical: Advanced Materials Research (Volumes 891-892)
• Pages: 1476-1481
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.891-892.1476
• Online since: March 2014
• Authors: Martin Cremer, Anton Kolyshkin, Martina Zimmermann, Hans Jürgen Christ
• Keywords: Aluminium Alloy, Fatigue Crack Growth (FCG), Stress Intensity Factor (SIF), Very High Cycle Fatigue (VHCF), Welded Joint

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