Effect of Heat Treatment T6 on Selected Properties and Structure of AlSi5Cu2Mg Alloy with Addition of Mo, Zr, and Sr

The hypoeutectic aluminum alloy AlSi5Cu2Mg is used for the production of high-strength automotive components such as cylinder head castings. AlSi5Cu2Mg alloy is characterized by a specific chemical composition (low permitted Si and Ti content) determined by the supplier. Due to the low permitted Ti content it is impossible to refine the grain structure of this aluminum alloy using standard grain refiners based on Al-Ti-B. Al-Si-Cu-Mg alloys are thermal stable up to the temperature 200°C, due to the presence of strengthening precipitates. Due to the downsizing, the operating temperature exceeds the temperature of 200°C, which leads to a decrease in the mechanical and physical properties of Al-Si-Cu-Mg alloys. The aim of this study is to analyse influence the alloying elements and heat treatment on the selected properties of AlSi5Cu2Mg alloys that are crucial for cylinder head castings. The paper focuces on the evaluation of the influence of selected alloying elements Sr, Zr and Mo on mechanical and physical properties. The present work also analysis the effect of heat treatment T6 on selected properties and structure of AlSi5Cu2Mg alloy modified by Sr, Zr or Mo. Sr, Zr and Mo were added into the AlSi5Cu2Mg alloy in the form of master alloys AlMo10, AlSr10 or AlZr20. According to the findings, the incorporation of the chosen alloying elements did not result in a substantial improvement in the mechanical and physical characteristics of AlSi5Cu2Mg alloy, which would be critical for its practical application. Physical and mechanical properties noted positive increase due to the effect of thermal processing T6.