Effect of Fe, Cr and Mn addition on the microstructure and mechanical properties on casting process of A356 alloy

Aluminium and aluminium alloys are widely used in the automotive, aerospace, and defense industries due to their high strength-to-weight ratio, corrosion resistance, and lightweight properties. The demand for aluminum is continuously increasing, and efforts are being made to improve aluminium's properties, which are insufficient on their own, by adding different alloying elements. Aluminum-Silicon (Al-Si) casting alloys are in demand in the market due to their properties such as superior castability, lightness and high corrosion resistance, thermal and electrical conductivity. The most important factors affecting the mechanical properties of Al-Si casting alloys are microstructure defects that may occur during casting. These defects can be summarized as porosity, microsegregation and bifilm defects. The morphologies of intermetallic phases are an important factor in the formation and organization of these defects, and intermetallic within the structure can become more harmless or beneficial with different additional alloy elements. In the study, manganese (Mn) was added to the A356 aluminum casting alloy at 3 and 6 hours of waiting time, iron (Fe) was added with a carbon steel rod at 725 and 775 degrees, chromium (Cr) and iron (Fe) was added with a stainlesssteel rod. The casting process was carried out in permanent molds where tensile, three-point bending and ladder samples were taken. The study determined that the metals added to the A356 aluminum alloy at different casting temperatures and waiting time parameters significantly affected the type, size, and morphology of the intermetallic formed in the alloy, and accordingly, remarkable changes occurred in the mechanical properties.