Refinement effect of Zirconium and Samarium on Al-4Mg cast alloy

Abstract This study aims at investigating the modification response of cast Al-4%Mg alloy to Zirconium or Samarium additions at high and low levels. Thermal analysis was used to evaluate the influence of Zirconium and Samarium. The solidification data represented the four main reaction peaks during solidification and had shown that both Zr and Sm play a role in refinement with a depression in solidification temperature. Moreover, Sm acts as a modifier as it had noticeable effect on retarding the recalescence temperature. Microstructure Examination was implemented by optical microscopy, image analysis software and scanning electron microscopy (SEM) with the aid of image analysis and Energy Dispersive x-ray spectroscopy (EDS). The results revealed the formation of new intermetallic phases such as agglomerates of Al_38.76MgZr_7.04Ti_0.52Fe_0.07 and Chinese script shapes of Al_25.28MgFe_2.77Sm_1.48. Accordingly, a noticeable grain size reduction is found with respect to the level of addition of Zr and Sm where Sm showed more refinement effect.