The regularities of changes in the composition and properties (micro- and nanohardness, HB hardness) of the structural components - α-solid solution and eutectic components of the AK7ch alloy (AL9) depending on the value of the addition of Al-Y-Ce-La master alloy are established. With an increase in the addition of Al-Y-Ce-La master alloy a sharp change is observed in the composition and properties of the structural components of the AK7ch alloy - α-solid solution Si in aluminum and eutectic α + Si, as well as complex-doped aluminides from Si, Fe and rear earth metals (REM). The structural components of the AK7ch alloy are identified with the addition of an increasing amount of Al-Y-Ce-La master alloy (α-solid solution of Si in aluminum, eutectic α+Si, complex-doped aluminides of rare-earth metals of variable composition AlxSiyREMz and AlxSiyFezREMν). A correlation between the solubility of silicon in α-solid solution and its microhardness is found. To increase microhardness of the eutectic and hardness of the AK7ch alloy, it is necessary to add the synthesized ligature in the amount of 0.1 wt.%.