## 3 Results and Discussion of the Research Results  
Figure 2 shows the microstructure of the AlSi7 Mg alloy after modification in accordance with the test plan (Table 2). Figure 3 shows the changes in the tensile strength of the AlSi7 Mg alloy with the modifiers in accordance with the test plan (Table 2). Figure 2: Microstructure the AlSi7 Mg alloy without modification (**a**) and after modification with (**b**) AlTi0.06, (**c**) AlB0.06, (**d**) AlTi0.06B0.06, (**e**) AlSi7, (**f**) AlTi0.06 Si7, (**g**) AlB0.06 Si7, (**h**) AlTi0.06B0.06 Si7. Figure 4 shows the changes in the elongations of the AlSi7 Mg alloy with modifiers in accordance with the test plan (Table 2). Figure 5 shows the changes in the Brinell hardness of the AlSi7 Mg alloy with modifiers in accordance with the test plan (Table 2). The AlSi7 Mg alloy without modifying additives, which is the first point of the research plan for Ti, B and Si at a lower level (Table 2), is shown in Figure 1a. The microstructure of this alloy consists of eutectic (\(\alpha+\beta\)) against the background of the dendritic primary \(\alpha\) phase (solid solution of silicon in aluminum). The eutectic \(\beta\) phase (solid solution of aluminum in silicon) occurs in the form of thick plates with differently oriented symmetry axes. The result is a low tensile strength of Rm = 138 MPa (Figure 3a), an elongation of A = 0.7% (Figure 4a) and a Brinell hardness of H = 51 HB (Figure 5a). After modifying the alloy with a master alloy with (0.06% Ti + Al), the \(\beta\) phase was still present in the form of plates. The partial parallel arrangement of the plate axes indicates the beginning of the stabilization of the crystallization process. This confirms the beginning of alloy modification (Figure 1b). This state was reflected in the mechanical properties: Rm = 150 MPa (Figure 3b), A = 2.2% (Figure 4b) and H = 56 HB (Figure 5b). After modifying the alloy with a master alloy composed of (0.06% B + Al), further standardization of the eutectic (\(\alpha\) + \(\beta\)) was found. The eutectic silicon in the dominant-part platelets have a clearly uniform orientation of the symmetry axis. A significant fragmentation of the alloy microstructure was also observed compared to the unmodified alloy (Figure 2a). The effect of eutectic fragmentation is an increase in the strength (Rm) to 156 MPa (Figure 3d), A = 2.9% (Figure 4d) and H = 58 HB (Figure 5d). After modifying the alloy (0.06% Ti + 0.06% B + Al), a lamellar eutectic (\(\alpha\) + \(\beta\)) was still obtained, but with a high degree of fragmentation (Figure 2d). Smaller dimensions of the dendritic \(\alpha\) phase were also obtained. The result of the microstructure refinement are higher mechanical properties than for the modification of the alloy with a master alloy containing only titanium or boron; Rm = 176 MPa (Figure 3e), A = 4.5% (Figure 4e), H = 61 HB (Figure 5e). The use of a master alloy consisting of only 7% silicon and aluminum to modify silumin resulted in a microstructure similar to the alloy without modification (Figure 2e). Similar observations concern the mechanical properties, where Rm = 139 MPa (Figure 3f), A = 0.7% (Figure 4f) and H = 51 HB (Figure 5e). The graphical form presenting the regression equation (Figure 5e) describing the hardness for the Si variable at both the lower and higher levels (Table 2) looks the same because this variable does not appear in the regression equation (it is insignificant at the statistical level of 0.05). This is confirmed by Figure 5a-d, in which the course of the function relative to the Si axis is independent of the silicon content (parallel to the axis). For silumin with the master alloy (0.06% Ti + 7% Si + Al), a microstructure was obtained, consisting of long, thick plates with parallel axes of symmetry occurring within the boundaries of individual grains (Figure 2f). Comparing this microstructure with the microstructure of the alloy after modification (0.06% Ti + Al), it was found that it had eutectic silicon platelets with smaller dimensions.