Improving the properties of TiC steel bonded cemented carbides by optimizing the slurry rheology, printing path and shape design of 3D gel printing

TiC steel bonded cemented carbide was modeled by an extrusion-based 3D gel printing(3DGP) method. The rheological behavior of slurry was studied to control the slurry extrusion and modeling. The effects of printing parameters, printing path and modeling complexity were researched to get a printed sample without defects. The results indicated that the slurry with a solid loading of 50 vol% (85 wt%) was prepared, and its viscosity change is very little during 24 h in case of a higher shear rate like a nozzle. The viscosity of the slurry decreases with increasing the extrusion pressure and nozzle diameter. The skewed pattern of filaments eliminated pores in printed samples in comparison with the rectangular pattern under the condition of straight lines of the printing path. Pores at the corners of a model can be eliminated by changing the printing path from concentric lines to zigzag lines or two sets of slanted parallel lines. The modeling complexity without a support structure can be revealed by printing tilt cylinders with different angles, and the local parts on a model with a tilt angle of <45° can be printed accurately without designing a support structure. Improving the 3DGP procedure based on these experiences, the TiC steel bonded cemented carbide samples had properties similar to those prepared by conventional powder metallurgy methods.