The influence of Sr and La simultaneous addition on the microstructure of the secondary Al-Si-Cu-Fe alloy was investigated in this paper. It was found that addition of Sr and La contributed to grain refinement, modification of the morphology of -Al, eutectic Si and -phase. The Fe9LaSi4 and SrSi2 phases were formed with simultaneous addition of Sr and La in the alloys. In addition, metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes occurring at different Sr and La content. The results indicated that the length of needle phase and the secondary dendrite arm spacing (SDAS) value were clearly decreased with the simultaneous addition of the Sr and La elements. When the ratio of Sr/La was fixed at 1:1 in the case of a total dosage of 0.12 wt.% (Sr+La), the mean values of needle phase length and SDAS size reached minimum. As far as the total dosage of (Sr+La) fixed at 0.12 wt.% with various ratio of Sr/La, the mean length of needle phase reached a minimum value at a Sr/La ratio of 1:1, whilst the minimum of mean SDAS value at the Sr :La ratio of 1:5.
