Transferproject T5

Tailored properties of PBF-LB/M components by local in situ alloy formation

Laser beam melting (PBF-LB/M) of metals allows for the fabrication of highly complex products with locally varied material properties by applying tailored processing strategies. By this, parts with a ductile core and wear resistant case can be generated. Goal of the transfer project T5 “Tailored properties of PBF-LB/M-parts through local in situ alloying” is to exploit the potentials of local in situ alloying for the manufacturing of highly complex parts with the aim of substituting energy- and cost-intensive (chemical) post-process heat treatments. The foundation for this project was laid within the Collaborative Research Centre 814 as different deposition methods (e.g. piezo-activated dispenser) have been developed for the local supply of powder materials. Next, the correlations between the process strategy in PBF-LB/M, amount of deposited powder, and the resulting mixing effects and element distribution need to be analysed fundamentally. Within this project, carbon-black-additivated hard phase particles will be used to improve both the surface hardness and wear resistance through the formation of a metal-matrix-composite. As additively manufactured parts typically possess a high surface roughness, alternative methods for post-processing these surfaces will also be studied. This will be done using laser polishing with modified intensity distributions for adjusting the surface tensions during laser polishing and thus reducing the final surface roughness of the workpiece compared to commonly used intensity distributions. Therefore, the correlation between energy input and intensity distribution, surface roughness as well as the corresponding surface material hardness will be analysed. The obtained results will be validated in product-specific tests to assess the potential of local in situ alloying for manufacturing optimized products.