## 2 Materials and Methods
### Rheological Characterisation  
Rheological characterisation of the prepared disks was performed by the rotational rheometer MCR 302 Anton Paar GmbH, Graz, Austria. For the binder systems (B) a cone-plate configuration with a diameter of 50 mm was used, while for the composites with 30 and 45 vol.% filler loading a plate-plate configuration with a diameter of 25 mm was used. For the composites with the highest loading, i.e., 60 vol.%, a serrated plate with a diameter of 25 mm was used to prevent wall slip of the composites during the measurements. The temperature for rheological tests followed the temperature of kneading (175 \({}^{\circ}\)C).  
For rheological characterisation strain amplitude tests at a constant frequency and frequency sweep tests at the constant strain in the linear viscoelastic range were performed. Both tests were  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Stage (No.)** & **Temperature (\({}^{\circ}\)C)** & **Pressure (MPa)** & **Time (Min)** \\ \hline
1 & 200 & 0.1 & 20 \\
2 & 200 & 5 & 10 \\
3 & 200 & 6 & 10 \\
4 & 200 & 7 & 10 \\
5 & 30 & 7 & 20 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Parameters used in the vacuum press during compression moulding of disk specimens.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Filler Material**} & \multicolumn{3}{c}{**Loading Level (Vol.\%)**} \\ \cline{2-4}  & **30** & **45** & **60** \\ \hline Aluminium alloy (Al) & Al\_30 & Al\_45 & Al\_60 \\
316L stainless steel (316L) & 316L\_30 & 316L\_45 & 316L\_60 \\ Titanium alloy (Ti) & Ti\_30 & Ti\_45 & Ti\_45 \\ Glass beads (GB) & GB\_30 & GB\_45 & GB\_60 \\ Binder (B) & B\_30 & B\_45 & B\_60 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Combinations of the prepared highly filled composites and their designated names.  
performed as shear deformation-controlled tests, where the samples were loaded with a time-varying shear strain, \(\gamma\) (t):  
\[\gamma\left(\text{t}\right)=\gamma_{0}\text{ sin }(\omega\text{t}) \tag{1}\]  
with amplitude \(\gamma_{0}\) and angular frequency \(\omega\). As materials exhibited viscoelastic behaviour, the response of materials was obtained as a phase-shifted (\(\delta\)) shear stress function, \(\tau\) (t):  
\[\tau\left(\text{t}\right)=\tau_{0}\text{ sin }(\omega\text{t}+\delta) \tag{2}\]  
where \(\tau_{0}\) represents the shear stress amplitude. We can further expand the expression for shear stress as:  
\[\tau\left(\text{t}\right)=\tau_{0}\text{ sin }(\omega\text{t})\text{ cos}\delta+\tau_{0}\text{ cos }(\omega\text{t})\text{ sin}\delta \tag{3}\]  
As it is shown in Equation (3) the stress consists of a component that is in phase with the strain and one being out of phase with the strain. The stress-strain relationship can thus be defined as storage modulus, G\({}^{\prime}\) that is in phase with shear strain and loss modulus, G\({}^{\prime\prime}\) that is out of phase with strain:  
\[\text{G}^{\prime}=\tau_{0}/\gamma_{0}\text{ cos}\delta \tag{4}\]  
\[\text{G}^{\prime\prime}=\tau_{0}/\gamma_{0}\text{ sin}\delta \tag{5}\]  
The storage modulus, G\({}^{\prime}\) represents the elastic behaviour of a material, while the loss modulus, G\({}^{\prime\prime}\) represents the viscous behaviour of a material.  
For each material, several repetitions of the same measurements were performed. Strain amplitude dynamic tests were performed at a constant frequency of 6.28 rad/s and by increasing strain amplitude from 0.01 to 100%. Frequency sweep dynamic tests were performed in frequency range 600 to 0.03 rad/s at the constant strain in the linear viscoelastic range, which depended on the sample and was for each sample previously determined by strain amplitude dynamic tests.