Enhancing density and geometric accuracy in multi-material AlSi10Mg-Cu parts by combining laser powder bed fusion and field-assisted sintering technology

Multi-material manufacturing enables the strategic placement of functional or costly materials only where necessary, enhancing both performance and resource efficiency, without the need of additional assembly operations. However, approaches such as multi-material laser powder bed fusion (PBF-LB) can be limited by metallurgical incompatibilities between materials. This study introduces a novel approach that combines the design flexibility of PBF-LB with the advantages of solid-state processing by field-assisted sintering technology (FAST). Specifically, AlSi10Mg preforms with controlled porosity are fabricated via PBF-LB and subsequently densified with a surrounding pure copper powder using FAST. The influence of preform density on the final density and geometric accuracy—both axial and radial—of the resulting multi-material components is investigated using a hemispherical interface. The proposed PBF-LB/FAST process is compared with selective powder deposition (SPD), where patterned powder layers are subsequently deposited and sintered. The PBF-LB/FAST route yields sharper material transitions and reduced cross-contamination than SPD, which produces more diffuse interfaces. However, porous preforms exhibit greater radial deformation than their SPD-fabricated counterparts under the axial pressure during FAST. This deformation can be mitigated with a bimodal Cu powder matched to the preform. Additionally, the bimodal powder led to multi-material parts with final densities higher than those achieved via SPD. • Porous PBF-LB preforms enable complex interface orientations in multi-material FAST. • Bimodal powder mitigates density mismatches between preform and powder. • Sharper material transitions and lower cross-contamination by PBF-LB/FAST than SPD.