Effect of Fe Content on Microstructure and Properties of Al-8Si-0.5Mg Alloy

Author of the article:SUN Bo, LIU Yujie, LIU Chunming

Author's Workplace：School of Materials Science & Engineering, Northeastern University, Shenyang 110819, China

Key Words：Al-8Si-0.5Mg alloy; Fe content; microstructure; mechanical property; electrical and thermal conductivity

Abstract：The effect of Fe on microstructure and performance of Al-8Si-0.5Mg alloy was studied by optical microscope (OM), scanning electron microscope (SEM) and hardness, tensile, electrical and thermal conductivity tests. The results show that with the increase of Fe content, the proportion of the second phase in the as-cast microstructure increases gradually, the secondary dendrite spacing decreases gradually, and the average length of the needle-like Fe-rich phase increases first and then decreases, and reaching the maximum 58 μm at 0.9% Fe. At the same time, the hardness of the alloy gradually increase, the electrical conductivity and thermal conductivity show a trend of gradual decrease, and the yield strength gradually increase. When 1.15% Fe, the hardness reaches the maximum 90 HV. The conductivity and thermal conductivity decrease by about 14% and 11% respectively. The yield strength increase by about 13.7%. With the increase content of Fe, the elongation will decrease by 48% when the Fe content is 0.9%Fe, and then it remains unchanged with the increase of Fe content.