A Laser Beam Welding Process and Its Microstructural Thermoelastoplastic Analysis

Laser beam welding has emerged as an advanced, contactless joining technique in recent years. This is primarily due to its high feed rates and low thermal distortion compared to conventional welding processes. These advantages stem from the focused energy input of the laser, enabling precise and controlled process 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. Despite its many 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. These critical states emerge in the mushy zone, which is located behind the weld pool and marks the transition between the fully liquid and solid phases. This region exhibits a dendritic microstructure, which 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 both macroscopic and microscopic levels. On a macroscopic scale, the mushy zone in the welded specimen is identified using suitable heat source models. On a microscopic scale, the evolving dendritic microstructure stemming from prior phase field simulations is analyzed, incorporating thermal and elastoplastic effects to capture the inherent stress and strain states. This two‐fold approach provides insights into critical conditions that may contribute to the identification of material failure.