Investigation of the effect of Nb addition on varying fe content in the Al11Si alloys

Aluminum casting alloys are widely preferred in many industrial applications, particularly in the automotive and defense industries, due to their advantages such as high strength, superior corrosion resistance, good thermal conductivity, and low density. However, with technological advancements, quality requirements in aluminum castings have been steadily increasing. In addition, due to environmental concerns, cost advantages, and the depletion of primary raw material resources, the use of secondary (recycled) aluminum in casting alloys has become increasingly important. On the other hand, it is well known that the use of recycled aluminum leads to the formation of brittle intermetallic phases, particularly due to the presence of iron (Fe), which adversely affects mechanical properties. In order to improve mechanical properties such as tensile strength, elongation, and fatigue life in aluminum casting alloys, porosity and structural defects must be minimized. Iron (Fe), one of the most detrimental elements affecting mechanical properties, reacts with other elements in the alloy to form various intermetallic compounds. These intermetallic phases have been widely reported in the literature to negatively affect mechanical properties, castability, porosity, corrosion resistance, and surface quality. In this context, studies have been carried out to reduce the negative effects of Fe and to meet the increasing quality requirements in casting alloys through the addition of various alloying elements and the use of advanced production techniques. In this study, casting experiments were carried out by adding niobium (Nb) to Al11Si primary alloys with different Fe contents obtained through diffusion. Thus, the effects of Fe and Nb elements in the alloy were evaluated through comprehensive experimental studies. Flowability, mechanical properties, and microstructural characteristics were analyzed in detail, and the effects of Nb addition were systematically revealed.