Consolidation and Characterization of Additively Manufactured Multi-Material Components for Electrical Machines

Korte inhoud:Electrical machines are essential components in a wide range of applications, including electric vehicles and renewable energy systems. However, conventional manufacturing methods constrain geometrical freedom and limit the integration of materials with distinct functional roles, thereby restricting further improvements in efficiency and performance. Multi-step additive manufacturing (AM) processes, particularly material extrusion (MEX), offer new opportunities to produce complex, multi-material components by sequentially depositing powder-loaded feedstocks and then densifying them at high temperatures. This work investigates both paste-based and filament-based MEX for the fabrication of dense and functional copper (Cu), electrical steel (Fe-6.5%Si), and 3 mol% yttria-stabilized zirconia (3Y-TZP) components. In addition to optimizing paste and filament formulations and printing parameters, the study focused on identifying suitable post-printing debinding and sintering conditions. Monolithic Cu parts were successfully fabricated by pressureless sintering in pure hydrogen at 1050 °C, whereas Fe-6.5%Si parts were consolidated in pure argon and vacuum at 1310 °C. These optimized conditions enabled the production of high-density, high-purity metallic components suitable for electrical machine applications. To enable co-printing and co-sintering of metals and ceramics, 3Y-TZP feedstocks were modified with 20-30 vol.% glass additive. The addition of glass tuned the ceramic's sintering trajectory, promoting densification at 1050 °C to better match Cu, and reducing shrinkage at 1310 °C to better match Fe-6.5%Si. This strategy enabled the fabrication of Cu/ceramic and Fe-Si/ceramic multi-material structures with flat or interlocked interfaces. Although local delamination and warping were observed, these were mitigated through interface design optimization, emphasizing the need for further refinement to address residual mismatches between materials. Additionally, another AM process called Selective Powder Deposition (SPD) was employed to produce laminated Fe-6.5%Si/3Y-TZP parts, subsequently consolidated by pressure-assisted sintering methods. The resulting multilayer structures exhibited stable architectures and magnetic performance competitive with conventional laminated steels, demonstrating the potential of SPD for laminated core fabrication. In summary, both MEX and SPD proved to be promising additive manufacturing approaches that overcome conventional processing constraints by exploiting the geometric and material design freedom of AM to fabricate advanced metallic and multi-material components for next-generation electrical machines.

Jaar van publicatie:2025

Toegankelijkheid:Embargoed