Title:

" Manufacturing of Nickel Based Superalloys Composites Using Binder Jetting Additive Manufacturing Process"

ABSTRACT:

Enhancing density of the parts manufactured by powder based additive manufacturing is time consuming, limiting the easy application of these AM processes. In this study, we show promising effects of graphene sheets as densifier agents for binder jetting of water atomized alloy 625 powders, enabling a more economical feedstock material than commonly used gas atomized powders. An approach called graphene encapsulating was used for in-situ production of graphene sheets decorating SiC particles during ball milling. The agglomerates were then mixed with water atomized alloy 625 powders and binder jetted using the ExOne printer. The microstructure and properties of the sintered composites were compared with printed and sintered gas and water atomized alloy 625 powders without using graphene.  

This study also demonstrates a significant effect of the graphene encapsulating process on diminishing the agglomeration of nanoparticles which is a crucial challenge in fabrication of metal and polymer matrix nanocomposites. We show a sponge-like capability of graphene sheets to nullify agglomeration tendency of nanoparticles during liquid phase sintering. This sponge morphology of crumpled graphene sheets stimulates circulation of liquid metals containing nanoparticles within solidifying semi-solid alloy 625 powders and thereby enhancing sintering density and microhardness of the fabricated composites.