Modellierung laser-induzierter Materialprozesse in der additiven Fertigung auf der Mikro- und Makroskala

In this dissertation, a process development for additive manufacturing of multi-material combinations by laser metal deposition is accomplished. The advancement of technologies for functional, thermal and optical multi-material components necessitates the use of novel and adapted material systems. With the objective of generating 3D-structures with these components in a single process step, the process influences on a powder-based coaxial laser metal deposition process are investigated. The successful generation of three-dimensional structures made from an adapted material system leads to the reduction of thermal expansion differences among the components in multi-material combinations. This is the basis for reducing thermally induced mechanical stresses in the operation of laser-optical or high-power electronic systems. Welding tests of iron-nickel and molybdenum-copper material systems are carried out. In comparison, the molybdenum-copper material shows advantages in terms of its low processing temperature and a nearly identical thermal expansion profile compared to the test specimen. With the addition of refractory metals and phosphor, an additively manufactured pseudoalloy can be produced. This pseudoalloy is characterized macroscopically by set material properties. Microscopically, the molybdenum particles are enclosed in the copper-phosphor matrix. The process development of the molybdenum-copper-phosphor material is carried out on an enhanced laser metal deposition system according to a multi-step statistical design of experiments. The evaluation reveals several significant process influences and mathematical prediction models are created. These models are used to determine suitable laser settings. The developed process window is transferred to a melt-pool size control system, which is distinguished from the state of the art by the use of a convolutional neural network. The combination of the determined process settings together with the intelligent process control and the adapted molybdenum-copper-phosphor material enables the additive manufacturing of property-adjusted pseudoalloys. With the developed process strategy, it has been possible to bond test specimens to metal and thus additively create first multi-material parts by means of laser metal deposition.