中國有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 21 No. 7 July 2011 |
Effect of bismuth on microstructure of unmodified and Sr-modified Al-7Si-0.4Mg alloys
S. FARAHANY, A. OURDJINI, M. H. IDRIS, L. T. THAI
（Department of Materials Engineering, Faculty of Mechanical Engineering,
Universiti Teknologi Malaysia, 81310, Malaysia）
Abstract:The effects of bismuth and the combination of bismuth and strontium on the eutectic silicon structure in Al-7Si-0.4Mg alloys were investigated under different solidification conditions. The results show that bismuth has a refining effect on the eutectic silicon and its refinement behavior increases with increasing Bi content up to 0.5% (mass fraction). When bismuth is added into the molten alloy modified with strontium, a higher Sr/Bi mass ratio of at least 0.45 is required to attain full modification of the eutectic silicon.
Key words: Al-Si alloy; bismuth; strontium; modification; eutectic solidification
