添加不同稀土元素對A356鋁合金之影響

Effects of Different Rare Earth Elements of A356 Aluminum Alloys

黃立仁(Lih-Ren Hwang) ； 胡浚銘(Jyun-Ming Hu) ； 鄭合志(Ho-Chi Cheng)

《鑄造工程學刊》 39卷2期 (2013/06) Pp. 1-10

摘要

本研究主要在探討添加不同稀土元素對A356合金機械性質之影響，因未經調質的A356合金，會形成針狀或平板狀的共晶矽，若加入調質元素，可使共晶矽的形狀轉變為纖維狀結構，而其工業中以鈉（Na）、鍶（Sr）、銻（Sb）等三種調質劑最為常用。本研究將以添加釔（Y）、鈧（Sc）、鈰（Ce）、鑭（La）等四種稀土元素作為調質劑，探討不同稀土元素對鋁合金微結構、抗拉強度、延伸率、衝擊強度及硬度的影響。實驗結果顯示，當稀土元素含量達0.05wt%以上時，共晶組織會由細長針狀或粗短棒狀轉變為纖維狀，當稀土元素含量增加時，機械性質均會隨含量增加而增加，但鑭元素含量增加時，抗拉強度會有下降之趨勢。

關鍵字

A356合金 ； 稀土元素

並列摘要

This study investigated the effects on the mechanical properties and reliability of A356 alloy major by adding various rare earth elements. As A356 alloy without conditioning would form needled or flat eutectic Si, adding conditioned elements could change the shape of eutectic Si into fiber-like texture. In industry, sodium (Na), strontium (Sr), and antimony (Sb) are the commonly used modifiers. By adding the rare earth elements of yttrium (Y), scandium (Sc), cerium (Ce), and lanthanum (La) as the modifiers, this study tends to discuss the effects of rare earth elements on the microstructure, tensile strength, elongation, impact strength, and hardness, as well as to precede reliability analyses of the mechanical properties. The experimental results show that the eutectic structure would change from thin, long needles or rough, short bars into filaments, when the content of rare earth elements achieves 0.05 wt.%; and the mechanical properties would increase with the increasing content of rare earth elements. However, when the content of lanthanum is increased, the tensile strength would be reduced.

並列關鍵字

A356 alloy ； Rare earth elements