Creating IN718-High Carbon Steel bi-metallic parts by Fused Deposition Modeling and Sintering

Bi-metallic materials allow to obtain new performances that are quite impossible to reach with ‘mono-materials'. When producing bi-metallic parts, variables to consider are, among the others, compatibility between the two alloys, their configuration and production technology. Fused Deposition Modeling and Sintering (FDMS) is a promising additive technology that is particularly suitable to produce such kind of components by using two metal/polymer composite filaments at the same time. A first attempt to produce Inconel 718-High Carbon Steel bi-metallic parts via FDMS with the aim to evaluate metallurgical features, relative density, part shrinkage, and interdiffusion mechanism at the interface between the two metals, is described. Different deposition patterns were evaluated while keeping the same debinding and sintering heat treatment. Despite sintering parameters were non optimized to reach a good densification, a good interdiffusion bonding between Inconel 718 and carbon steel was reached. The work highlighted the main issues to be faced in order to reach sound 3D printed bi-metallic parts.