FEATURES OF CONTROLLING THE SOLIDIFICATION RATE OF ALUMINUM AND MAGNESIUM ALLOYS IN LOW-PRESSURE CASTING

Abstract

The article is devoted to the study of the specific features of controlling the solidification rate of aluminum and magnesium alloys during low-pressure die casting, with the aim of ensuring structural homogeneity, reducing thermal stresses, and minimizing casting defects. Since the solidification rate significantly affects the formation of the alloy’s microstructure and, consequently, its performance properties, the study emphasizes the importance of precise thermal regulation at different stages of the solidification process. The influence of design and thermokinetic parameters–such as wall thickness, volumetric geometry, mold thermal conductivity, and gating system configuration– on the cooling intensity and phase transition duration under variable temperature gradients (arising during mold filling at pressures up to 0.06 MPa) is analyzed. A comparative assessment of the cooling dynamics in castings made of magnesium and aluminum alloys is performed, taking into account their physical and chemical properties (specific heat, thermal conductivity, density) and heat exchange mechanisms with the mold. It is established that optimization of local solidification rates through variation in wall thickness, application of cooled inserts, mold temperature control, differentiated cooling channels, and strategic placement of venting openings significantly reduces common casting defects such as shrinkage cavities, microporosity, delamination, and gas inclusions. The experimental findings are validated through CFD-based numerical modeling, which enables accurate prediction of melt behavior in the mold and identification of critical areas requiring additional thermal correction. The results obtained are practically relevant for the design of castings with specified mechanical properties and for the implementation of innovative approaches in serial and mass production of lightweight alloy components operating under high requirements for density, sealing, and dimensional accuracy.