Effects of S and Sb Additions on the Microstructure and Mechanical Properties of the Al–Si 319 Alloy

AbstractThis work shows the effect of simultaneous additions of sulphur and antimony on the microstructure and mechanical properties of the Al–Si 319 alloy, containing high levels of iron and manganese. It was found that sulphur and antimony act independently. The sulphur influences the shape and distribution of the Al15(Fe,Mn)3Si2 phase, promoting its occurrence as dendritic Chinese script-like morphology. On the other hand, antimony additions help in the formation of a lamellar eutectic structure. As a result of these changes in microstructure, an improvement in the values of ultimate tensile strength, elongation to failure and hardness was observed with respect to those shown by the untreated 319 alloy. The concentration ranges of antimony and residual sulphur investigated were 0.10–0.30 and 0.001–0.04 wt %, respectively. Resume Cette etude montre l'effet d'additions simultan'es de soufre et d'antimoine sur la microstructure et les proprietes mecaniques de l'alliage Al–Si 319 contenant un haut niveau d...