The present work investigates the influence of titanium, zirconium, copper, nickel and tantalum on the mechanical properties of the Al Si7Mg0,3Cu0,5 alloy. At the beginning of the work a detailed literature research was carried out, referring to the influence of the alloying elements, the grain refining and the heat treatment effect on the microstructure formation and the mechanical properties. Within the scope of this work four series of experiments were carried out. For this purpose, melting experiments were performed and then the microstructure was analysed for phases and grain sizes by means of a light microscope and a scanning electron microscope. In the result section a comparison of the alloys with respect to their properties is given.