Einfluss der separaten Materialzuführung auf die Schichtzusammensetzung beim Hochgeschwindigkeits-Laserauftragschweißen; 1. Auflage

Coatings for surface finishing are becoming increasingly important across various industries to meet growing demands, such as mechanical, thermal or chemical exposure. These coatings can extend service life of components and reduce friction. In particular, the use of laser-based High-Speed Directed Energy Deposition (HS DED-LB) offers great advantages for an efficient coating process and effective coating due to its process characteristics like productivity, achievable material combinations, material and energy efficiency. Depending on application, powder material mixtures or multi-layer coating systems are increasingly used for surface coatings. Challenges arise with material mixtures in which the respective material properties, such as powder morphology or melting temperature, differ. Depending on these properties, process parameters have varying influences on the behavior of the materials during the process and the resulting coating properties. A solution involves moving the material mixing into the laser beam through further developing the powdered material supply into a separate material supply with two independent powder gas streams (PGS) with adjustable powder focus positions. The developed powder feed can be positioned relative to each other within the three spatial dimensions. This allows control over the interaction time between powder particles and the laser beam by managing the interaction path and particle velocity. In this way, the mixing behavior can be influenced in terms of homogeneous or separating solution behavior of the materials across the layer height. The influence of the separate material supply on the coating are still un-known and is being investigated and characterized within the scope of this work. The conveying gas volume flow rate (CGVF) has a major influence on particle velocity and powder focus position. An FE simulation using ANSYS Fluent is carried out to identify the influence of the CGVF on both the individual PGS and the interaction of the PGS with each other. Subsequently, the process influences of the parameter variation process speed, laser spot diameter and FGVS on the Si content in the matrix AISI 316L of the Metal Matrix Composite (MMC) AISI 316L and SiC are analysed by means of PGS displacement in z-direction. The feasibility study for producing a single-layer graded coating is conducted using the PGS displacement in the x-direction. Finally, the knowledge gained is demonstrated in two applications: the control mirror of an axial piston pump and brake disc of a rotary module.