The hypoeutectic aluminum alloy AlSi5Cu2Mg is used for the production of high-strength cylinder head castings. The alloy is unique for its specific low permitted Ti content (0.03 wt% max), which makes it impossible to refine the grain structure of this alloy using standard Al–Ti–B grain refiners. The specific chemical composition is specified by the supplier company. The aim of this paper is to find a suitable alloying element that would improve the selected properties (e.g., mechanical, and physical properties) that are crucial for cylinder head castings. The research focuses on the investigation of the effect of different Zr addition (0.05; 0.10; 0.15 and 0.20 wt% Zr in the form of AlZr20 master alloy) on the properties of AlSi5Cu2Mg in the as-cast state and after heat treatment T7. The obtained results showed that ultimate tensile strength, yield strength, hardness, and physical properties of as-cast samples do not change significantly with increasing Zr content. The experimental alloys showed a more significant increase in ultimate tensile strength, yield strength, hardness, and thermal conductivity after heat treatment T7. Zirconium-rich intermetallic phases were observed in the shape of separate thick needles or as a cluster of two crossed thinner needles.

The paper focuses on the investigation of the influence of Ti on selected properties of the hypoeutectic aluminium alloy AlSi5Cu2Mg. AlSi5Cu2Mg alloy finds application in the field of production of high-strength cylinder head castings intended for the automotive industry due to the optimal combination of mechanical, physical and foundry properties. In commercial production, the maximum Ti content is limited by the manufacturer (Ti max. = 0.03 wt.%), which significantly limits the possibilities of refinement the alloy with Ti-based grain refiners. Therefore, the possibility of increasing the Ti content beyond the manufacturer's recommendation is considered in this work. The main aim of the work is to evaluate the influence of graded Ti addition (0.1; 0.2; 0.3 wt.% Ti) on the resulting mechanical and physical properties of the AlSi5Cu2Mg alloy. Simultaneously, the influence of increased Ti content on the microstructure of AlSi5Cu2Mg alloy is evaluated. The alloying element was introduced into the melt in the form of AlTi5B1 master alloy. The effect of T6 heat treatment on the resulting mechanical and physical properties and microstructure of the hypoeutectic AlSi5Cu2Mg alloy with graded Ti addition was also investigated in the experimental work.

The paper deals with the solubility and influence of the melting method of alloying elements (Zr, Mo and Sr) on selected properties and structure of the hypoeutectic aluminum alloy AlSi5Cu2Mg. Alloy-ing elements in the form of master alloys (A...

Al-Si-Cu-Mg-based alloys are key materials for applications in the automotive and aerospace industries, mainly due to their low density, excellent castability, and high specific strength. However, their mechanical properties are often negatively affected by the presence of brittle, acicular eutectic silicon particles and long intermetallic phases with a high iron content, which have a negative impact on the overall toughness and strength of the material. This study systematically focuses on evaluating the individual and combined effects of microalloying with varying amounts of tungsten and T7 heat treatment on the microstructure of the hypoeutectic AlSi5Cu2Mg alloy. The results obtained showed that the addition of tungsten significantly refines the microstructure of the alloy already in the cast state. There is a reduction in the coarse-grained morphology of the primary α-Al phase and a significant refinement of the eutectic silicon, which changes its original shape to a finer and more compact one. At higher tungsten concentrations, extensive clusters of fine grains were observed, indicating its effective role in the heterogeneous nucleation of the eutectic phase. Another key finding is its ability to suppress undesirable iron-rich intermetallic phases, particularly β−Al5FeSi acicular structures, which are transformed into shorter and more compact shapes. The combination of tungsten and T7 heat treatment further enhanced the synergistic effect and accelerated the spheroidization of eutectic silicon, promoting the formation of an almost perfect spheroidal morphology. At the same time, a significant modification of the Fe-phase shape to a less critical morphology was achieved.

Al-Si-Cu based alloys are key structural materials in industry due to their favorable combination of low weight, casting, and mechanical properties. In recent years, the influence of refractory metal additions has been investigated, with tungsten being a subject of interest for its potential to influence the crystallization process. This work deals with the effect of tungsten addition on the microstructure and porosity of the AlSi5Cu2Mg alloy. The experimental alloy was alloyed with tungsten in concentrations of 0.05, 0.10, and 0.15 wt.%. The addition of tungsten showed a significant effect on the size of the primary a(Al) phase dendrites as well as on the morphology of the eutectic silicon. The most significant refinement of the dendritic network was observed at the highest concentration of 0.15 wt. % W. Analysis of microporosity revealed that while the 0.05 wt.% W addition suppressed pore formation, higher concentrations led to its significant increase in the as-cast state.

This article analyzes the influence of beryllium (Be) as an alloying element on the structural properties of the AlSi5Cu2Mg alloy. Specifically, it examines the ability of Be to affect crystallization and the electrical and thermal conductivity. The goal is to implement a non-standard alloy into a low-silicon aluminum alloy that would show improved physical properties, refined structure, and stabilization of intermetallic phases. Such a modified alloy could be used for large aluminum castings in the automotive industry, especially for lightweight electric vehicles. It's also suitable for castings requiring balanced mechanical properties and high ductility, as well as for special high-pressure die casting (HPDC) parts that demand higher physical properties than standard aluminum alloys. The analysis shows that adding Be in the range of 0.05, 0.08, and 0.12 wt.% to the AlSi5Cu2Mg alloy refines the grain and changes the morphology of the eutectic silicon. Using a separated remelting method with AlBe5, no Be burnout occurred in the alloy. An addition of 0.12 wt.% Be to the tested alloy resulted in an increase in both electrical and thermal conductivity.