Laser-Based Additive Manufacturing and Characterization of an Open-Porous Ni-Based Metallic Glass Lattice Structure (Ni60Nb20Ta20).

Due to their amorphous structure, metallic glasses exhibit remarkable properties such as high strength, hardness, and elastic strain limit. Conversely, they also exhibit high susceptibility to brittle fracture, making them less qualified for the use as monolithic structural components. Therefore, they may be preferably used as the reinforcing phase in hybrid materials combined with ductile matrix materials. Especially metal matrix composites with interpenetrating structures are suitable. This requires an open-porous structure of the metallic glass. In the study at hand, an open-porous lattice structure was manufactured from metallic glass powder (Ni60Nb20Ta20) by laser powder bed fusion. A parameter study was carried out with various scanning strategies to manufacture a mechanically stable lattice structure while maintaining the amorphous structure of the metallic glass. Thus, X-ray diffraction measurements were conducted to validate the parameter study. A stable lattice structure with a largely amorphous structure was successfully achieved with a scanning strategy of single scanned lines and a rotation of 90° for each layer. However, nanocrystallization of 7% occurred in the heat-affected zones formed between the individual printed layers during reheating. Conducting compression tests, a compressive modulus of 18 GPa and a maximum strength of 90 MPa in 0°-direction were achieved. In 90°-direction, no compressive modulus could be determined but compressive strength resulted in 15 MPa. Performing nanoindentation with a Young's modulus of 195.1 GPa and Vickers hardness of HVIT = 956.1 was achieved for the printed bulk metallic glass alloy. The resulting lattice structure was further characterized by differential scanning calorimetry for thermal behavior.

Characterization of the Metal Fused Filament Fabrication Process for Manufacturing of Pure Copper Inductors.

This work presents a comprehensive investigation into the optimization of critical process parameters associated with metal fused filament fabrication (Metal-FFF) for the production of copper-based components. The study focused on three different commercial and one self-manufactured filament, each with unique chemical compositions. These filaments were systematically optimized and the density was characterized for all processing steps, as well as the electrical conductivity on the specimen scale. Remarkably, two of the studied filaments exhibited exceptional properties after sintering with forming gas (up to 94% density and 55.75 MS/m electrical conductivity), approaching the properties measured for established manufacturing methods like metal injection molding. Finally, the research was extended to component-scale applications, demonstrating the successful fabrication of inductors with integrated cooling channels. These components exhibited water tightness and were used in induction hardening experiments, validating the practical utility of the optimized Metal-FFF process. In summary, the results show great promise in advancing the utilization of Metal-FFF in industrial contexts, particularly in the production of high-performance copper components.