Influence of laser beam welding with overlaid high-frequency beam oscillation on weld seam quality and fatigue strength of aluminum wrought and die-cast joints

Laser beam welding of aluminum die cast components using high frequency beam oscillation could massively improve the process stability and tightness of cooling components. The application of the newly developed laser beam welding processes to fatigue loaded components makes it necessary for designers to dimension the components and welds using existing guidelines. Up to now, however, no experience has been obtained with the applicability of the existing regulations. For this purpose within this study, weld specimens in form of aluminium mixed joints (wrought and die-cast alloys) were produced with standard laser beam welding process (LBW) and laser beam welding with overlaid high-frequency beam oscillation (LBW-HF). The weld seam quality is correlated with the fatigue strength properties. Furthermore, the results from the fatigue tests are classified in the existing IIW regulations and their applicability with regard to laser-welded aluminium joints will be discussed. The results show an increased fatigue strength, especially for the LBW-HF process, compared to current used standards for design.