In recent years, nanotechnology is increasingly applied to improve the mechanical properties of additively manufactured materials using laser-based powder bed fusion (PBF-LB). This can be achieved by grain refinement. The microstructure exhibits globular and smaller grains after addition of a nuclei agent (nanoparticles). Within the special priority program (SPP) 2122, New Materials for Laser-based Additive Manufacturing, funded by the German Research Foundation (DFG), alloying elements that might form nuclei or pre-defined nanoparticles act as grain refiner, as well as modification methods, are investigated. The main objective is to enable the processability of materials such as high-strength aluminum alloys of the 7xxx series with PBF-LB.

The powder modification of AA 7075 with titanium carbide (TiC) nanoparticles allows the production of crack-free and dense parts. Hence, one main goal is to determine the necessary amount of nuclei agent to meet the requirements for strength values and elongation at break after PBF-LB. Different modification processes are considered, for example, ball milling, atomization with and without pre-modification. Furthermore, the effectivity as nuclei agent of different nanoparticles (type, size), with regard to the modification method is investigated. The aluminum alloy°7075 can be processed successfully using PBF-LB resulting in a relative density of 99.89 %. An ultimate tensile strength up of 330 MPa and an elongation at break of 10.8 % in the as-built condition are achieved. The addition of 2.5 wt% TiC nanoparticles results in a significant grain size reduction (≈ 2 µm in diameter).