Effect of Input Parameters on the Structure and Properties of Castings Obtained via Crystallization under Pressure

Abstract

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.