近共晶Al-Si合金的晶粒细化  

Grain refinement for near-hypoeutectic Al-Si alloys

作　　者：孙瑜[1] 吴振平[1] 柳秉毅[2] 孙国雄[1] 

机构地区：[1]东南大学材料科学与工程系 [2]南京工程学院材料科学与工程系,南京210023

出　　处：《中国有色金属学报》2004年第8期1340-1347,共8页The Chinese Journal of Nonferrous Metals

摘　　要：研究了Al Sr变质剂和锆复合盐细化剂对高近共晶Al Si合金宏观/微观组织的影响。结果表明:单一Al Sr变质剂的加入,不仅改变了共晶硅的形貌,同时对合金的组织也有较明显的细化作用。这可能是由于锶的加入,改变了液态金属的结构,导致枝晶尖端前沿生长过冷度增加,降低了枝晶α(Al)固液界面能。当Al Sr变质剂和锆复合盐细化剂共同作用时,随着熔体中锆含量的增加,铸锭的晶粒度显著减小,当熔体的锆含量超过0.35%,可获得细小、分布均匀的等轴晶,其宏观晶粒尺寸为100～120μm。与Al Zr中间合金相比,无论是细化效果还是抗衰退的能力都优于中间合金。The influence of Al-Sr modifier and Zr compound salt on marco/micro structure of near-hypoeutectic Al-Si alloys was investigated. Only the addition of Sr into Al-Si alloys could result in transition of eutectic silicon from coarse plate-like or acicular to fine fibrous, at the same time it had also a better refinement to the structure of alloys. The present of Sr in Al-Si alloys causes the changes of structures of liquid metals, and leads to the decreases of the solid-liquid interfacial energy of dendrite α(Al) and increases of the growth undercooling of dendrite tips. The combined addition of Al-Sr and Zr compound salt, with increaseing the Zr content, the grain size decreases obviously. Finer and evenly equiaxed dendrite α(Al) is attained with addition of 0.35% Zr, and the size of macrostructure grain is about 100120 μm. The Zr in compound salt forms into the Al-Si alloys melt, compared to Al-Zr master alloys, the ability of grain refinement and resistant fading are better than those of Al-Zr master alloys.

关 键 词：Al—Si合金 变质 晶粒细化 宏观 微观组织 

分 类 号：TG146.21[一般工业技术—材料科学与工程]