Additive manufacturing process and microstructure during powder extrusion printing of cemented carbides

Abstract

Powder extrusion printing (PEP) is an additive manufacturing (AM) technology based on the combination of traditional metal injection molding and 3D printing, which has the advantages of wide range of printable materials and low cost. The PEP process of WC-13Co cemented carbide was studied, including the development and properties of thermoplastic printing materials, such as the dispersity, rheology and formability. The effects of debinding and sintering process on the microstructure and mechanical properties of the final parts were also investigated. The results show that the specialized binder for PEP of cemented carbides has been prepared successfully. EDS analysis demonstrates that the binder is uniformly dispersed in the green body. The binder can be effectively and totally removed from the green body by two-step debinding process. In combination with vacuum sintering at 1450 ℃ for 60 min, high performance of cemented carbide sample with the shrinkage rate of 17.8%, uniform distribution of WC grain size, and Vickers hardness of 1410HV30 is successfully fabricated. The result confirms that the PEP technology can be applied to prepare cemented carbide materials with high performance and controllable print size, which provides an effective technical route for additive manufacturing of cemented carbide.

Keywords

• cemented carbide
• additive manufacturing
• powder extrusion printing
• microstructure
• mechanical property