## 3 Results
The slurry with a solid loading of 46 vol % possessed a shear viscosity of 393.5 mPa-s at the shear rate of 100 s\({}^{-1}\) and an intimal viscosity less than 1000 mPa-s, which is enough to meet the requirements of gel casting. The shear stress versus shear rate in Figure 5 could be further analyzed using the Herschel-Buckley model [28]:  
\[\tau=\tau_{0}+\text{k}\text{yn} \tag{1}\]  
Figure 3: Effects of the PVP dispersant amount on the rheological properties of the TiH\({}_{2}\)/Al slurries. where \(\tau\) is the shear stress, \(\tau_{0}\) the yield stress, k is a consistency coefficient, \(\gamma\) is the shear rate, and n is the flow behavior index. According to the rheological properties of the TiH\({}_{2}\)/Al slurries shown in Figures 3 and 4, it is evident that the slurries belong to typical pseudoplastic fluids [28]. In order to avoid cracking during demolding, the strength of the gel-casted body must be considered while fabricating complex-shaped parts. Figure 5 shows the effect of monomer contents on the flexural strength of the green bodies. It can be seen from Figure 5 that with the increase of the monomer contents from 15 to 40 vol %, the flexural strengths of the green bodies increased from 28.86 to 62.36 MPa. This might be due to the increasing monomer content bringing more polymer networks in per unit volume, leading to increased strength. Figure 6 shows the fracture micrograph of TiH\({}_{2}\)/Al green bodies with different monomer contents when the solid loading is 46 vol %. It can be seen from Figure 6 that when the gelled polymer contents in the green bodies are relatively low (Figure 6a-d), the spherical state of the Al particles can still be observed, while the TiH\({}_{2}\) particles are also encapsulated by the polymer and partly covered by Al particles. Meanwhile, there are some pores in those bodies. Some of the pores could be attributed to the pull-out of the TiH\({}_{2}\) particles when the green body was broken off. It was also found from the experiment that when the monomer content is too high (for example, over 35 vol %), the slurry solidifies quickly and is not easy to control. Meanwhile, in the processes of degreasing and sintering, more polymer in the green bodies might lead to more residues, which would have adverse effects on  
Figure 4: Effects of the solid loading on the rheological properties of the TiH\({}_{2}\)/Al slurries. Figure 5: Effect of monomer content on flexural strength of dried bodies derived from the 46 vol % TiH\({}_{2}\)/Al slurry. the properties of the sintered bodies. Therefore, the suitable monomer dosage determined in this study was 30 vol %. Figure 7 shows the thermogravimetric curve of the green body with a monomer content of 30 vol % and a solid loading of 46 vol %. As can be seen from Figure 7, the thermogravimetric curve of the TiH\({}_{2}\)/Al green body can be divided into four stages (s1-s4). The first stage is from room temperature to 300 \({}^{\circ}\)C. In this temperature range, the weight loss of the sample is about 2%, which corresponds to the  
Figure 6: Cross-sectional micrographs of TiH\({}_{2}\)/Al green bodies gel casted from slurries with different monomer contents. (**a**) 15 vol %, (**b**) 20 vol %, (**c**) 25 vol %, (**d**) 30 vol %, (**e**) 35 vol %, and (**f**) 40 vol %. volatilization of the solvent and the initial decomposition of the gelled polymer. The second stage is from 300 to 500 \({}^{\circ}\)C. In this temperature range, the weight loss of the sample is about 9%, corresponding to the massive decomposition of the polymer network, and the DTG curve also indicates that the decomposition rate reaches its maximum value near 418 \({}^{\circ}\)C. The third stage is from 500 to 620 \({}^{\circ}\)C. The weight of the sample remains unchanged, indicating that the burning of the polymer is basically completed, but TiH\({}_{2}\) does not dehydrogenate obviously.