## 3 Results and Discussion
Three primary diffraction peaks of aluminum with the highest intensity were identified in S1. The peak at 20 = 38.396\({}^{\circ}\) is characteristic of the (111) plane of the aluminum crystal lattice, corresponding to the characteristic diffraction of aluminum with a cubic lattice. Figure 4: LM and SEM images of S1, S1-HT, S2, and S2-HT specimens. The peak width at half height (FWHM = 0.241\({}^{\circ}\)) indicates relatively large crystals in the material, suggesting that the material did not have significant microstructural defects. The peak at 20 = 44.727\({}^{\circ}\) is the base aluminum peak, which is also characteristic of the (200) plane. The high peak height indicates the dominance of the aluminum phase in the material. The narrow peak line confirms the good crystallinity of the aluminum in the specimen. The peak at 20 = 65.111\({}^{\circ}\) indicates aluminum corresponding to the (220) plane. The high intensity and narrow peak line also confirm the high degree of crystallinity of the material. S1 is composed mainly of aluminum with a high-quality crystal lattice, but trace phases other than pure aluminum are present, possibly with the presence of aluminum oxide (Al\({}_{2}\)O\({}_{3}\)) or carbon impurities formed by contact with oxygen (O) in air or carbon (C) in the graphite crucible. These peaks had much lower intensities and widths, which may indicate the presence of phases in smaller amounts. For S1-HT, it was possible to identify three primary aluminum peaks with the same planes as for S1 and close values of the 20 angle: peak 20 = 38.503\({}^{\circ}\) aluminum in the (111) plane, peak 20 = 44.745\({}^{\circ}\) aluminum in the (200) plane, and peak 20 = 65.133\({}^{\circ}\)aluminum in the (220) plane. The results showed that the crystallite sizes in the peaks ranged from 715 to 887 A. Although this indicates the presence of sufficiently large crystalline regions in the specimen, these values are much more homogeneous than those of S1, which range from 364 A to 1746 A, indicating the possible presence of fine- and coarse-grained phases. The diffraction peaks at 20 = 38.398\({}^{\circ}\), 20 = 44.636\({}^{\circ}\), and 20 = 65.038\({}^{\circ}\) for S2 suggested that the main phase in the specimen was aluminum. For S1 and S1-HT, these peaks correspond to the characteristic diffraction planes (111), (200), and (220), respectively. These narrow peaks indicate a high-quality aluminum crystal lattice without significant defects, indicating that the aluminum crystals were relatively large. The reinforcing microsilica used in the composite primarily exhibits microcrystalline characteristics, as evidenced by the broad peaks with lower intensities at angles 20 = 34.576\({}^{\circ}\), 20 = 40.123\({}^{\circ}\), and 20 = 58.067\({}^{\circ}\). These peaks suggest a partially ordered structure of the microsilica particles, as opposed to a purely amorphous material, which lacks long-range atomic order. The characteristic diffraction peaks for aluminum in the S2-HT composite correspond to angles 20 = 38.610\({}^{\circ}\), 20 = 44.855\({}^{\circ}\), and 20 = 65.242\({}^{\circ}\), representing the (111), (200), and (220) planes, respectively. Figure 5: XRD patterns of S1, S1-HT, S2, and S2-HT specimens. The peaks associated with the reinforcing microsilica at 20 = 34.791\({}^{\circ}\), 20 = 40.37\({}^{\circ}\), and 20 = 58.267\({}^{\circ}\), as well as an additional peak at 20 = 63.25\({}^{\circ}\), indicate its presence as a mixed-phase material with microcrystalline regions. These peaks are broader and less defined than those of aluminum, reflecting the partial disorder in the structure of microsilica. The performance improvement of the composite can be attributed to the reinforcing effect of the microcrystalline microsilica. The partially ordered structure contributes to stress distribution and impedes crack propagation, enhancing both strength and ductility.