MODIFICATION OF THE HYPO-EUTECTIC Al-Si ALLOYS WITH AN EXOTHERMIC MODIFIER

Results of studies on the modification of AlSi7Mg alloy with an exotherimc modifier are presented in the paper. MgO, Cr2O3, Na2O2, NaNO3, Na2MoO4 were used as modifiers in the amount of 0.05, 0.10, 0.15, 0.20 and 0.25%, and Cr2O3+Al, NaNO3+Al, Na2MoO4+Al were applied as exothermic modifiers with Al as the reducing agent in the amount of 0.04-0.3%. The analyzed modifiers were incorporated in line with factorial design 2(3). The Inmold modification method was applied. The microstructure of selected modified alloys was presented, and their tensile strength, percentage elongation and Brinell hardness number were given in graphic form. The results of the study indicate that the use of modifiers delivering an exothermic effect influences the effectiveness of silumin modification.