## 3 Results and Discussion  
The microstructural analysis of all samples, as illustrated in Figure 3, provides critical insights into the influence of sintering parameters (sintering time, sintering temperature, and compaction pressure) on material densification. The micrographs of specimens S1, S2, and S3 reveal significant porosity, primarily attributed to the lower compaction pressure applied during processing. This results in inadequate particle rearrangement and reduced packing density, leading to an increased presence of micro-voids. A direct correlation was observed between compaction pressure and porosity reduction. As compaction pressure increases, the material exhibits improved particle cohesion, which minimizes void formation. Additionally, sintering time and temperature play a crucial role in enhancing densification. Prolonged sintering duration coupled with elevated sintering temperatures facilitate enhanced atomic diffusion and grain boundary migration, promoting effective pore elimination. The combined effect of these parameters accelerates mass transport, reducing residual porosity and increasing overall density. The micrographs of the S9 specimen, subjected to the highest compaction pressure, extended sintering time, and elevated \begin{table}
\begin{tabular}{c c c c c c} \hline
**Symbol Notation** & **Control Factor** & **Unit** & **Level 1** & **Level 2** & **Level 3** \\ \hline A & Compaction & MPa & 250 & 300 & 350 \\  & pressure & & & & \\ B & Sintering & \({}^{\circ}\)C & 500 & 550 & 600 \\  & temperature & & & & \\ C & Sintering time & min & 45 & 60 & 75 \\ \hline \end{tabular}
\end{table} 
Table 4: Control factors and their levels. \begin{table}
\begin{tabular}{c c c c} \hline
**Sample** & **A** & **B** & **C** \\ \hline S1 & 250 & 500 & 45 \\ S2 & 250 & 550 & 60 \\ S3 & 250 & 600 & 75 \\ S4 & 300 & 500 & 60 \\ S5 & 300 & 550 & 75 \\ S6 & 300 & 600 & 45 \\ S7 & 350 & 500 & 75 \\ S8 & 350 & 550 & 45 \\ S9 & 350 &sintering temperature, exhibit a significant reduction in micro-voids. This improvement is attributed to enhanced diffusion kinetics, which results in more efficient reinforcement distribution within the matrix material. The uniform dispersion of reinforcement phases, coupled with optimized sintering conditions, contributes to improved mechanical integrity and superior densification. These findings highlight the interplay between processing parameters and microstructural evolution, emphasizing the necessity of optimizing sintering conditions for superior composite performance. The XRD pattern for AZ31/1.75 wt.% GNP composites at different processing parameters was mainly analyzed to reveal the presence of different phases and peaks present in the composites. The formations of peaks and phases were directly linked to the processing parameters. The peaks and phases obtained are the results of processing parameters of powder metallurgy (mixing the powders, compaction pressure, and sintering time and temperature). Therefore, the result mainly depicted the presence of the \(\alpha\)-Mg phase in all the composites formed. The absence of \(\beta\)-Mg\({}_{17}\)Al\({}_{12}\) phase peaks in all the compositions was detected in the XRD. Other than peaks and phases depiction, the results of XRD were also crucial in analyzing whether AZ31 alloy reacts with GNP or not since the absence of peaks related to interfacial products was consistent in all the compositions of AZ31/GNP composites. This provides suitable evidence that there was no reaction taking place between the matrix and reinforcement. Other than that, no literature has indicated the reaction of Mg with GNP. The presence of the MgO peak provided evidence of strong covalent and ionic interaction at the interface between Mg/MgO and MgO/graphene. This replaced the weak van der Waals bonding between graphene and Mg alloy and provided a hindrance to the dislocations. Hence, the existence of the MgO phase is assumed, finding a resemblance with the strong interfacial bonding strength between the matrix and reinforcement.