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Laser beam welding has emerged as an advanced, contactless joining technique. This is primarily due to its high feed rates and low thermal distortion compared to conventional welding processes, [1]. These advantages stem from the focused energy input, enabling precise and controlled execution. Additionally, the automation potential of laser beam welding broadens its applicability across various industries, including automotive and aerospace engineering, shipbuilding, medical technology, electronics, and tool manufacturing, [2]. Despite its benefits, the process is not without challenges, particularly the formation of solidification cracks. These cracks develop during the solidification phase, originating from microcracks within the weld bead and propagating to the surface as cooling progresses, [3]. These critical states form in the mushy zone, which forms behind the weld pool and contains the transition between the fully liquid and solid phases. This region exhibits a dendritic microstructure that can trap liquid inclusions. When these inclusions solidify, the absence of liquid replenishment generates critical material states, potentially inducing stresses that lead to crack formation. This study addresses the issue on macroscopic and microscopic levels. On a macroscopic scale, the mushy zone in the welded specimen is identified using suitable heat source models, [4,5].On a microscopic scale, the evolving dendritic microstructure stemming from prior phase field simulations, [6], is analyzed, incorporating thermal and elastoplastic effects to capture the inherent stress and strain states. This dual approach provides insights into critical conditions that may contribute to the identification of material failure.
[1] M. Dal and R. Fabbro. An overview of the state of art in laser welding simulation. Optics \& Laser Technology, 78, 2-14, 2016.
[2] U. Dilthey. Schweißtechnische Fertigungsverfahren 1: Schweiß- und Schneidetechnologien, 3., bearbeitete Auflage ed., Springer-Verlag: Berlin, Heidelberg, 2006.
[3] E. Folkhard, G. Rabensteiner, E. Pertender, H. Schabereiter and J. Tösch. Metallurgie der Schweißung nichtrostender Stähle, Springer-Verlag: Vienna, 1984.
[4] A. Artinov, V. Karkhin, N. Bakir, X. Meng, M. Bachmann, A. Gumenyuk and M. Rethmeier. Lamé curve approximation for the assessment of the 3D temperature distribution in keyhole mode welding processes. Journal of Laser Applications, 32, 022042 (8 pages), 2020.
[5] P. Hartwig, L. Scheunemann and J. Schröder. A volumetric heat source model for the approximation of the melting pool in laser beam welding. Proceedings in Applied Mathematics and Mechanics, 23(4), e202300173, 2023.
[6] M. Umar, D. Schneider and B. Nestler. Solidification of quaternary X5CrNi18-10 alloy after laser beam welding: A phase-field approach. Procedia CIRP, 124, 460-463,2024.
