Poisoning effect of bismuth on modification behaviour of strontium in LM25 alloy

被引：13

作者：

Farahany, S. ^{[1
]}

Ourdjini, A. ^{[1
]}

Idris, M. H. ^{[1
]}

Thai, L. T. ^{[1
]}

机构：

[1] UTM Skudai, Fac Mech Engn, Dept Mat Engn, Johor Baharu 81310, Malaysia

来源：

BULLETIN OF MATERIALS SCIENCE | 2011年 / 34卷 / 06期

关键词：

Thermal analysis; bismuth; modification; aluminium alloy; SILICON;

D O I：

10.1007/s12034-011-0239-5

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Nucleation and growth, temperature measurements and microstructure 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 degrees C and recalescence decreased to 0.2 degrees C and the morphology of silicon displayed the same flake-like 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.

引用

页码：1223 / 1231

页数：9

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