Modification mechanism of cerium on the Al-18Si alloy

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• 作者：Henghua ZHANG ; Haili DUAN ; Guangjie SHAO ; Luoping XU ; Junlin YIN ; Biao YAN
• 关键词：metal material ; modification mechanism ; thermodynamics analysis ; rare earth element ; hypereutectic Al-Si alloy
• 刊名：Rare Metals
• 出版年：2006
• 出版时间：February 2006
• 年：2006
• 卷：25
• 期：1
• 页码：11-15
• 全文大小：1132 K

文摘

The effect of the rare earth cerium (Ce) on the hypereutectic Al-Si alloy under different casting states have been studied by optical microscope and quantitative image analysis. It is found that the size and the quantity of primary silicon in castings decrease with the increase of added Ce in the melt. Meanwhile primary silicon changes from branched shape to fine facetted shape. Although the modification on eutectic silicon in castings also improves with the increase of added Ce in the melt, the effect of modification on eutectic silicon away from primary silicon is more obvious than that on eutectic silicon close to primary silicon. The modification mechanism was analyzed in detail by means of scanning electron microscope equipped with energy dispersive analysis of X-ray and thermodynamics analysis, which included the analysis on the change in standard Gibbs energy of reaction and reaction equilibrium.