Review of Process–Structure–Property Relationships in Metals Fabricated Using Binder Jet Additive Manufacturing

This review aims to identify process–structure–property relationships in metals fabricated using binder jet additive manufacturing. Binder jet differs from fusion-based additive manufacturing methods, such as powder bed fusion or directed energy deposition, in that the metallic component is processed without melting. The three primary stages in the binder jet process are: green body fabrication, de-binding, and post-processing, all of which have numerous variables that impact the microstructure and mechanical properties. The effects of powder characteristics, processing parameters, and post-processing conditions on porosity and mechanical properties are discussed based on data compiled from literature. Results indicate that sintering temperature and environment are more impactful for density and mechanical properties than sintering time. Binder jetting presents opportunities to rapidly fabricate components out of a wide range of materials; however, the large number of variables with intertwined impacts on structure and properties requires additional modeling and characterization efforts toward the development of optimized protocols for binder jetting. Additionally, efforts toward reliable part certification methods, particularly with nondestructive evaluation techniques, are needed for the improvement and adoption of binder jetted metals in a broader range of critical applications.