Effects of different binder systems on the characteristics of metal-based diamond composites fabricated via fused deposition modeling and sintering technology

Abstract

In material extrusion of metal-based composites, binder system plays a vital role and its performance directly influences the quality of the final product and process efficiency. Despite different binder systems have been produced, most studies only concentrated on single binder system without comparison between different binder systems. In this work, two different binder systems were used to fabricate metal-based diamond composites by fused deposition modeling and sintering technology. Morphology of printed metal-based composites samples were compared. Thermal properties of composites samples with different binder systems were analyzed via TG-DSC test, and debinding was carried out at heating rate of 5 °C/min and 2 °C/min, respectively. Then the brown samples were densified via hot-pressing sintering, and the sintered samples were evaluated by scanning electron microscopy, hardness tester and universal testing machine. During the printing process, the feedstock using TP-based binder system exhibited better printing performance compared with that using the PW-based binder system. The results also revealed that appropriate nozzle temperature should be determined according to the thermal properties of the feedstocks so as to minimize printing defects. The debinded samples with different binder systems can retain structural integrity when the heating rate controlled properly. As for the samples after sintering, it has to be highlighted that the hardness on the top surface of the sintered sample was higher than the hardness on the side because of different deposition characteristics. In addition, the samples using TP-based binder presented a more uniform microstructure and thus obtained better flexural strength and relative density. It can be concluded that the TP-based binder is preferable as it contributes to better performance of the metal-based diamond composites compared with the PW-based binder.