## 3 Results and Discussion of the Research Results
By analyzing the changes in mechanical properties after the modification of the silumin with the master alloy with a variable share of titanium (Figure 7) and boron (Figure 8), it was found that the AlSi7 Mg alloy after the modification with the master alloy (Ti3B + AlSi7) has the highest properties. In the third series of tests, it was decided to determine the optimal share of the Ti3B component in the master alloy. For this purpose, it was decided to modify the hypoeutectic silumin with the master alloy (Ti3B + AlSi7) (Figure 9). Figure 8: Mechanical properties the AlSi7 Mg alloy without modification and after modification with AlSi7 + (TiBx) master alloy for Ti = 0.06% and B from 0.06% to 0.3%: (**a**) tensile strength, (**b**) elongations, (**c**) Brinell hardness. After the modification of silumin (AlSi7 Mg) with the (0.04% Ti3B + AlSi7) master alloy, the tensile strength (Rm) = 171 MPa (Figure 9a), elongation (A) = 4.5% (Figure 9b) and hardness (H) = 61 HB. After increasing the amount of the modifier to 0.06%, the mechanical properties increased to Rm = 176 MPa, A = 5.1% and H = 62 HB. The highest mechanical properties of the analyzed parameters were obtained for the master alloy given above. After modifying the AlSi7 Mg alloy with the (0.08% Ti3B + AlSi7) master alloy, a change in all analyzed mechanical properties was achieved within the error limits: Rm = 175 MPa, A = 5.2% and H = 63 HB. When further increasing the Ti3B in the master alloy to 0.1 and 0.12%, the strength decreased to 171 and 169 MPa, the elongation to 4.9 and 3.3%, and the hardness to 62 and 57 HB, respectively. It should be remembered that the amounts of titanium and boron discussed refer to the same mass of each of them in relation to the mass of the modified alloy. The analysis of the test results presented in Figure 9 shows that the highest mechanical properties were obtained for 0.06 to 0.08% (Ti3B + AlSi7). By analyzing all the presented results of the mechanical properties (Figure 9), it was decided to check whether by increasing the amounts of both modifiers from 0.06% to 0.1% (basic share) it would be possible to obtain similar modification effects reflected in the mechanical properties of the processed AlSi7 Mg alloy. For this purpose, research was carried out on the modification of the AlSi7 Mg alloy with the master alloy (AlSi7 + Ti + B) for 0.1% Ti and 0.1% B at the basic level TiB (1:1) and for a larger amount of titanium--respectively, Ti2B (2:1), Ti3B (3:1), Ti4B (4:1) and Ti5B (5:1) (Figure 10). Figure 9: Mechanical properties the AlSi7 Mg alloy after modification with AlSi7 + (Ti3B) master alloy: (**a**) tensile strength, (**b**) elongations, (**c**) Brinell hardness. The AlSi7 Mg alloy after modification with the (TiB + AlSi7) master alloy obtained Rm = 169 MPa (Figure 10a), A = 4.4% (Figure 10b) and H = 60 HB (Figure 10c). The highest mechanical parameters were obtained for the master alloy containing 0.2% titanium and 0.1% boron (Ti2B), amounting to Rm = 173 MPa, A = 5.0% and H = 62 HB. After increasing the proportion of titanium to boron to Ti3B, the mechanical parameters of the modified silumin decreased to Rm = 170 MPa, A = 4.6% and H = 61 HB. Subsequently, when the proportion of titanium to boron was increased, the analyzed mechanical properties were further reduced for Ti4B to Rm = 167 MPa, A = 4.4%, H = 59 HB, and for Ti5B to Rm = 163 MPa, A = 3.5%, H = 58 HB. Therefore, for the share of Ti at the level of 0.1% and boron at the level of 0.1% (Figure 10), a different course was obtained for different Ti/B ratios in the master alloy than with the share of each of them at the level of 0.06% (Figure 7). It follows that the efficiency of a master alloy containing titanium and boron depends not only on the ratio of titanium to boron, but also on their share in the master alloy in relation to the mass of the modified alloy. Analyzing the presented research results, it was found that the problem is not easy and unambiguous to describe.