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The constant need for the development of new alloys with an improved ratio between weight and strength is the driving force for the progress of the present work, which deals with the production of a new Al-cast alloy with the addition of lithium (Li). 0.8 wt% Li was added to the AlSi7Mg alloy. The solidification behaviour of such a new alloy was the focus of the work. The melt was produced in an inert gas atmosphere in an induction furnace. The solidification behaviour was described by CALPHAD simulations, optical microscopy, scanning electron microscopy (SEM) and simple thermal analysis. In addition, the Vickers hardness (HV) was measured 29 days after casting and compared with the results of the AlSi7Mg base alloy. Solidification proceeds somewhat differently from the base alloy, where the liquidus temperature is raised to 637 °C, where the primary AlLiSi phase forms, followed by αAl dendrites, eutectic βSi and other phases in the form of eutectics, which are known to occur during solidification of the AlSi7Mg alloy. The hardness of the new alloy is increased compared to the base alloy, especially at higher cooling rates, where the hardness gain is up to 36%.

The technology of casting with crystallization under pressure-squeeze casting belongs to unconventional pressure-casting methods. The melt or material in a semi-solid state is pressed under pressure until the casting solidifies completely. The input parameter, whose influence was mainly observed in this paper, is the state of the material entering the filling process. The alloys were in a molten and semi-solid state. The influence of casting thickness from 3.15 mm to 8 mm was also observed. Alloy AlSi7Mg0.3 was used because of the wide solidification interval and the significant influence of pressure during solidification. Consequently, alloy AlSi12 was subjected to experimental work because processing in the semi-solid state is not sufficiently examined for this material. A significant influence of the cooling rate in different cross-sections on the structure and mechanical properties of castings made using squeeze casting technology was confirmed. The difference in mechanical properties was approximately 35% for both eutectic and hypoeutectic alloys. When processed in a semi-solid state, it was confirmed that the network of dendrites has a significant influence on the filling of the mold cavity. The paper also focuses on the effect of input material morphology on the final product properties. The change in morphology was achieved by metallurgical intervention, thermal and technological processing.