A study on the sinterability and properties of binder jet 3D printed Invar36 powder blends

Binder Jetting, despite it its mainly directed to high-productivity additive manufacturing purposes, it also offers a high accuracy fabrication route for less common metal alloys or for special purpose applications. In the present work, an exploration of the printing process and sinterability of different invar36 alloy powder bimodal mixtures is performed. Invar36 is a Fe-Ni alloy which presents near zero CTE below its curie temperature (279°C) and it is widely used for high precision instrumentation in space environment. MIM grade <22µm powder and fine <5 µm Invar36 commercial powders were used as raw materials. Printing process parameters were selected based on a previous parameter optimization study [1], and printed test samples were sintered in a vacuum atmosphere. Sintered parts were characterized and the CTE was measured. The results of the study showed that bimodal Invar36 powders can be properly tailored and manufactured for tuning the part densification to desired values.