## 2 Experimental Approach  
Commercially available aluminum powder (Fe: 0.1%; Mn: 0.02%; Ti: 0.03%; Cu: 0.02%; Si: 0.1%; and balance Al) with a mean particle size of 46.16 \(\upmu\)m was used for the preparation of the test specimens. In addition, laboratory-based non-metallic ceramic particles such as alumina (aluminum oxide (Al\({}_{2}\)O\({}_{3}\))) and silicon carbide (SiC) were blended with the aluminum powder to make four varieties of composite materials, each containing a different volume fraction of the ceramic particle reinforcements. The blending process was carried out using a planetary ball mill (FRITSCH, Pulverisette 6) at 100 rpm for 30 min with a zirconium ball (5 mm diameter) to a powder ratio of 10:1. The properties of the chosen metal matrix and the two chosen reinforcements are summarized in Table 1. The # indicates the values that were experimentally determined and * indicates the properties from the supplier (for the Al and Al\({}_{2}\)O\({}_{3}\) powder (Loba Chemie Pvt. Ltd., Mumbai, India) and for SiC (Alfa Aesar, Mumbai, India)). The chemical composition of the chosen materials is provided in Table 2.  
The homogeneous powder mixture was cold compacted using a cold uniaxial press with a metallic die with an inner diameter of 10.2 mm. A mixture of 1 g, 2 g and 3 g (\(\pm\) 0.080) of the powder mixture was taken for the purpose of compaction to produce a solid with an H/D ratio of 0.5, 1.0 and 1.5, respectively. The homogeneous powder mixture was initially pressed in a cold uniaxial pressing machine (make: SOILLAB; type: hydraulic) to obtain \"green\" cylindrical test samples that had an outer diameter of 10 mm. The compacted samples were subsequently sintered in a tubular furnace in an atmosphere of argon gas. The sintering cycles are shown in Figure 1; those used for making the hybrid Al MMCs are listed in Table 2. The sintering temperatures were the furnace temperatures where one (700 \({}^{\circ}\)C) was near to the melting point of Al. Three different sintering times, 30 min, 60 min and 90 min, at a furnace temperature of 700 \({}^{\circ}\)C were selected for the purpose of sintering in order to both study and establish its influence on the density, hardness and microstructure evolution for the Al/7 vol.% SiCp. The sintered Al/7 vol.% SiCp composites that had a different modulus (m = 1.25, 1.67 and 1.87) are shown in Figure 2. The composites (Al/7 vol.% SiC) shown in Figure 2 were used for the purpose of the measurement of the density, hardness and microstructure to examine the modulus effects. The sintered Aluminum MMCs, as shown in Table 2, were further compressed to a 50% reduction in height using a tensile test machine (model: [PERSON], 50 KT). In addition, these composites were also \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Material** & **Mean Particle Size (\(\upmu\)m) \#** & **Young’s Modulus (GPa) \({}^{*}\)** & **Tensile Strength (MPa) \({}^{*}\)** & **Coefficient of Thermal Expansion (10\({}^{-4}\) K\({}^{-1}\)) \({}^{*}\)** & **Density (g/cm) \({}^{*}\)** \\ \hline Al\({}_{2}\)O\({}_{\mathrm{sp}}\) & 1.27 & 360–400 & 250–300 & 8.5 & 3.95 \\ SiC\({}_{\mathrm{sp}}\) & 8.13 & 400–440 & 310 & 4.8 & 3.2 \\ Al & 46.16 & 70 & 200 & \(22.2\times 10^{-4}\) & 2.7 \\ \hline \end{tabular}
\end{table} 
Table 1: Properties of the consumables (#: measured at particle level, \({}^{*}\): measured at sample level after sintering). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Composites** & **Volume Fraction (\%)** & **Weight for 10 g of Aluminum** \\ \hline Al MMCs (Al/SiC/Al\({}_{2}\)O\({}_{3}\)) & Al/2–SiC/8–Al\({}_{2}\)O\({}_{3}\) & 2 and 7 vol.\% of SiC & 0.375 SiC + 0.692 Al\({}_{2}\)O\({}_{3}\) \\ Al MMCs (Al/SiC/Al\({}_{2}\)O\({}_{3}\)) & Al/7–SiC/3–Al\({}_{2}\)O\({}_{3}\) & 3 and 8 vol.\% of Al\({}_{3}\) & 1.387 SiC + 0.731 Al\({}_{2}\)O\({}_{3}\) \\ Al/7–SiC/8–Al\({}_{2}\)O\({}_{3}\) & 1.468 SiC + 2.065 Al\({}_{2}\)O\({}_{3}\) \\ \hline \end{tabular}
\end{table} 
Table 2: Composition of the aluminum metal matrix composite.