Integrating indirect additive and conventional manufacturing to produce hybrid metallic components

Abstract

International audienceHybrid additive manufacturing (AM) integrates distinct fabrication routes to reduce production costs and time whilepreserving design freedom. This work introduces a novel hybridization strategy that combines an indirect sinter-basedAM process, namely material extrusion (MEX), with conventional manufacturing (CM) to produce integrated metalliccomponents in 17-4PH stainless steel. The approach exploits the shrinkage of the MEX part during sintering to promotebonding with the conventionally manufactured counterpart. The bonding mechanism between MEX-fabricated hollowcylinders and conventionally manufactured rods of the same alloy was investigated. Hollow MEX cylinders were debindedand dried prior to inserting CM rods into their cavities, followed by sintering to induce shrinkage-driven consolidation atthe interface. The hybrid parts were characterized using dimensional measurements, mechanical testing and microstructuralobservations. Hybridization increased the overall length and modified the external diameter near the upper regionof the MEX zone. Mechanical tests revealed two distinct behaviors, with a maximum apparent adhesion strength of39.8 ± 1.5 MPa before decohesion. Depending on the local surface roughness, the interface exhibited both open and closedregions. Furthermore, hybridization reduced the inter-filament gaps in the vicinity of the MEX contours and decreased thesize of sintering pores at the interface