Estudio del efecto del hierro en las propiedades mecánicas de una aleación de aluminio-silicio (A 356)

Abstract

The main objective of the present work is the analysis of the effect of iron on the mechanical properties of alloy A 356. For the melting process was used degassing with noble gases, chemical degassing, flux and grain refinement. The addition of the iron was made from an Al-10% Fe master alloy. Samples were prepared for 4 different compositions by weight percentage of iron (0,44; 0,8; 1 and 1,2%). The samples were subjected to tensile and hardness tests, finding a slight decrease of the ultimate tensile strength with the increase of iron content. The main effect was the reduction of elongation to the fracture (ductility) and the increase in hardness. In addition, a study of the microstructure of the samples was carried out, where the formation of the β intermetallic phase of stoichiometry Al5FeSi and monoclinic structure and platelet morphology was identified by X-ray diffraction. Finally, the average length of the β-phase platelets was determined, finding a direct relation of their value with the iron content and the cooling rate was estimated, which turned out to be low, typical of a sand mold foundry.