The choice of process gas plays a pivotal role in determining the properties of materials processed by laser-based additive manufacturing. By strategically combining process gases and materials, manufacturers can not only tailor hardness and dilution but also reduce operational costs—key factors for advancing industrial laser materials deposition (LMD) applications. In this study we investigate the impact of various process gases on laser material deposition process, emphasizing their effects on melt pool dynamics, microstructure, layer quality, hardness, and process costs. Using 316L powder, a disk laser, and the process gases argon, helium, nitrogen, and CO₂, we conducted experiments analyzing single track geometry, hardness, microstructure, and deposited volumes. The results highlight CO₂ as a distinct process gas, exhibiting unique effects on dilution, microstructure, and hardness that set it apart from the other gases and offer potential for tailored applications.

Powder properties are considered an important factor for part quality in additive manufacturing using lasers, although few studies have investigated effects in directed energy deposition (DED-LB). Water atomized (WA) and gas atomized (GA) powders are frequently used but may lead to different part properties due to differing powder properties. To examine their qualification for DED-LB, this work examines GA and WA powders of AISI 316 and build quality. Results show that the atomization method shows no relevant influence on porosity and Archimedian density of built parts. Also, WA powders show good processability in DED-LB, despite unfavourable morphology. In contrast to this are mechanical properties: WA specimen reach only 9 % elongation where GA based reach 33 %. Tensile strength of both are below 580 MPa. As a reason, defects and oxides can be assumed. Cheaper WA powders with less favorable morphologies could still be used for DED-LB, when load requirements are low.

In laser-based directed energy deposition (DED), a well-aligned powder stream relative to the laser beam is essential for maximizing process efficiency and minimizing material loss. A detailed understanding of powder stream propagation is therefore critical. In this study, high-speed imaging was used to investigate particle behavior within the powder stream. Using a multi-step evaluation method, the mean velocity, velocity variations, and flight direction of individual particles were determined. Powder channels with varying surface roughness—ranging from Ra = 2.16 µm to 0.27 µm—were tested to assess their influence on stream characteristics. The results reveal that lower channel roughness leads to increased mean particle velocity and significantly narrower flight angles. Specifically, the divergence angle decreased by approximately 61%, which suggests the potential for a more focused powder stream and reduced material loss. These findings offer valuable insights into optimizing powder delivery systems for enhanced efficiency and precision in laser-based DED processes.

EN AW-7075 (AlZn5,5MgCu) is a high strength aluminum alloy for aerospace applications suffering from poor weldability due to solidification cracking susceptibility. In this study, crack free Laser Metal Deposition (LMD) of EN AW-7075 is enabled by adding up to 1 %vol of TiC-nanoparticles (35-55 nm) to the powder feedstock. It was found that nanoparticles are successfully incorporated into the melt pool where they provide for a grain refinement due to inoculation, and thereby eliminate hot cracking.

Moreover, the addition of nanoparticles enhances the absorption of the laser wavelength in the powder (as measured with an Ulbricht sphere) and was found that the incoupling efficiency of the processing laser beam was increased which affects the melt pool dimensions and further helps to prevent lack of fusion defects in processes with the same parameters.

There is currently a requirement of the market to produce brake disks which produce minimum fine dust emissions: the euro 7 emissions rules for automotive sector. For this reason, it is necessary to improve the wear resistance of the brake disk.

A wear coating using EHLA (Extreme High-speed Laser Application) is one of the most popular solutions, however, it has been observed that the adherence between the coating and the material of the brake disk, is usually poor due to the presence of lamellar graphite in the cast iron.

This work presents an optimized laser pre-cleaning process of the brake disk surface prior to the application of EHLA. Coating experiments using 430L were performed with and without laser pre-cleaning. The results of the experiments demonstrate that the pre-cleaning removes graphite from the surface and reduces the porosity in the coating, thus achieving an improved metallurgical bond between the two materials.

Additive manufacturing (AM) of steel is gaining traction in the construction industry, offering the ability to fabricate complex geometries and optimize resource use. Among the AM techniques, Laser-Based Powder Directed Energy Deposition (DED-LB) is notable as it provides a compromise of relatively high productivity with respect to powder bed fusion and fine resolution with respect to arc based DED processes. However, the common steel grades often encounter challenges in meeting construction requirements, including limited compatibility with conventional structural steels concerning bolted and welded assemblies. This study tackles these challenges by developing the DED-LB process with a novel high-strength steel powder feedstock. Through an extensive experimental campaign, the research evaluates the processability of the material, focusing on achieving dense and crack-free steel components. The results highlight optimized deposition strategies providing high mechanical strength, opening new possibilities for its adoption in the construction sector for medium to large sized products.