Aluminum alloys based on Al-Si-Cu, including the AlSi9Cu1 alloy, are among the most widely used aluminum alloys in the automotive and engineering industries due to their excellent combination of mechanical properties and good castability. To improve the properties of Al-Si-Cu-based alloys, the addition of small amounts of specific alloying elements is commonly used. In the presented research, titanium and zirconium are added to the aluminum alloy AlSi9Cu1. These elements act as effective grain refiners, promoting the formation of a fine-grained primary aluminum structure and influencing the size of the eutectic phases. Ti and Zr in the microstructure form intermetallic particles Al 3 Ti and Al 3 Zr, which serve as heterogeneous nucleation centers, preventing the growth of large dendritic and lamellar structures. The results of the present study show that the addition of Zr at a level of 0.10 wt.% led to a refinement of the primary matrix and a related modification of the eutectic Si. The formation and presence of Al 3 Zr-based phases, characterized by their stability at elevated temperatures, make the alloy suitable for use at higher temperatures. The subsequent addition of Ti to the alloy led to a significant reduction in the SDAS factor, resulting in a fine-grained and homogeneous microstructure composed of small primary α-phase grains and eutectic Si in the form of smaller rods. The results confirm that the presence of these elements significantly enhances the quality and performance of the alloy, making it suitable for applications in the automotive and aerospace industries.
Kantoríková et al. (Thu,) studied this question.