Laser welding has become an increasingly popular substitute for traditional arc welding over the past two decades, due to its versatility, enhanced process speed, and minimized heat-affected zone. However, many industries, such as civil, naval, or heavy-duty machinery, must conduct extensive testing campaigns to incorporate this new technology. Experimental campaigns demand many resources for each parameter variation, hindering their economic feasibility, especially for components and structures of high-added value. As an alternative, numerical simulations provide a virtual framework for analyzing welding processes, enabling the evaluation of the effects of various process parameters on the resulting structures. In this study, a finite element thermo-mechanical model is developed using ANSYS to investigate and compare diverse welding configurations and parameters. The study focuses on butt-welded S275JR steel plates using ER70S-6 filler wire. Key findings include the extent of the heat-affected zone and its implications for distortions and residual stress distributions.

Extruded recycled 6060 aluminium alloys are highly susceptible to hot cracking during laser welding due to their thermal and mechanical properties. This study focuses on developing a thermo-mechanical model to predict crack formation during laser welding of recycled AA6060 alloys with varying Cu content. A finite element model was developed, incorporating a parametrised adjustable ring-mode heat source to simulate transient temperature fields and thermal stresses.

To evaluate crack susceptibility, welds were simulated with varying edge distances to alter thermal stress and temperature distribution. Based on the thermal and mechanical behaviour of the weld pool and heat-affected zone, a stress-based index is being developed to quantify the risk of crack formation. This model aims to provide insights into optimizing welding parameters, offering practical guidance for industries such as automotive and aerospace manufacturing.

Recent advancements in dynamic beam shaping have shown the potential to revolutionise the welding process. Although this is a very attractive proposition, knowledge about the temporal and spatial response of the process to dynamic beam shaping is yet required. This study implements a multi-kW CW laser with a coherent beam combiner (CBC) and optical phased array (OPA) to modulate the fluence distribution at the microsecond scale. It investigates solidification cracking susceptibility using individual free-form beam profiles generated in the kHz regime and sequences of beam profiles switched at the microsecond time scale. A self-restraint cantilever hot cracking test was conducted on AA6082 1.5 mm sheets with full-penetration single bead-on-plate welds. Metallography analysis with electron backscatter diffraction (EBSD) was employed to correlate material microstructure with the tested beam shapes. The results are presented to highlight the unique features of modulated fluence distribution as well as current challenges and new research avenues.

High-strength aluminum alloys offer excellent weight-specific mechanical properties, making them an ideal choice for parts in electromobility applications like battery trays. However, their susceptibility to transverse hot cracking during laser welding at high welding velocities is challenging. This study investigates the mechanisms of transverse hot crack formation by means of numerical simulations of the temperature field and melt flow in the melt pool and validates the results with experiments. The results reveal a critical zone at the side of the melt pool which is characterized by a high static pressure drop at the liquidus isotherm as a result of high melt flow velocities and cooling rates, which affect the intergranular melt flow during solidification. The study provides valuable findings, which enable the optimization of high-speed laser welding of aluminum alloys, to avoid the formation of transverse hot cracks.

Aluminium alloys of the 7xxx series are renowned for their exceptional strength due to Mg and Zn precipitations. However, the presence of these precipitations reduces the ductility and thus the formability of these alloys, hindering their application for shaping operations e.g. in the automotive sector. One promising approach to improve the formability of this material class is by selectively evaporating these precipitation-promoting elements exploiting their lower evaporation temperature compared to the aluminium matrix. A spatially resolved evaporation can be achieved by localised laser remelting.

In this work, we present results on the selective element evaporation for AA7075. Key characteristics for describing the process are the evaporated amount of elements, the evaporation depth and gradients along z-direction. Cross-sections are analysed using EDX to determine the elemental distribution. Finally, element evaporation is correlated with melt pool size and the applied processing strategy to assess the potentials of a specific laser process.

With increasing competition in the EV market, reducing costs and improving thermal management in battery cases became critical for sustainable growth. This study investigated a multi-materials integration via laser welding. To achieve the dissimilar materials joining, the aluminum surface was coated using a pure Fe powder cold-sprayed processing. Disk laser welding was performed to join the dissimilar materials. The laser processing was recorded using a CCD, IR camera. This data was used to develop a CNN model to classify weld penetration depth. Mechanical, microstructural, and corrosion characteristics were analyzed. Depending on the welding parameters, the mechanical properties of the joint and intermetallic compound formation varied. However, the variation in mechanical properties was not significant because the fracture path progressed through the cold-sprayed layer. The fracture path was only influenced on penetration depth.