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      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/034/06/1223-1231

    • Keywords

       

      Thermal analysis; bismuth; modification; aluminium alloy.

    • Abstract

       

      Nucleation and growth, temperature measurements andmicrostructure observations of silicon phase are presented for strontium modified Al–7%Si (LM25) cast alloy treated with bismuth. The results show that addition of bismuth in strontium modified alloys may have a poisoning effect resulting in lost modification of the silicon phase. With increasing Bi/Sr ratio, thermal analysis measurements showed that the eutectic growth temperature increased remarkably to 573°C and recalescence decreased to 0.2°C and the morphology of silicon displayed the same flakelike structure as in the unmodified alloys. Microstructural observation showed that a minimum Bi/Sr ratio of 1.2 which is equivalent to a Sr/Bi ratio of 0.43 is required for effective strontium modification and neutralization of the poisoning effect of bismuth.

    • Author Affiliations

       

      S Farahany1 A Ourdjini1 M H Idris1 L T Thai1

      1. Materials Engineering Department, Faculty of Mechanical Engineering, UTM Skudai, 81310 Johor, Malaysia
    • Dates

       

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