AA5083鋁合金鋁胚均質後表面黑色凸點成因之研究

Evolution of Black Cauliflower-like Precipitate on The Surface of AA5083 Slab after Homogenization

游瑞坤(J. K. Yu) ； 呂競忠(C. C. Lu) ； 詹金生(C. S. Chan) ； 許國峰(K.F Hsu)

《鑛冶：中國鑛冶工程學會會刊》 50卷4期 (2006/12) Pp. 153-162

https://doi.org/10.30069/MM.200612_50(4).0011

摘要

黑色凸點發生位置皆位於AA5083鋁胚表面的復熔點及澆鑄環，經放大觀察發現其構造乃由數個小黑點所組成，形狀酷似花椰菜，內部則有很多孔洞，下方之母材也有很多孔隙，甚至是氣孔。其主要組成相為純度遠高於母材之αAl及MgO，形成原因主要與晶界Al-Mg共晶相熔化及蒸發有關，其晶界則成為共晶相蒸發途徑，並在鋁胚表面氧化而產生黑點。此外，鋁胚表面形成黑色凸點位置下方，多數在均質前即有氣孔存在，或在表面具有凹孔，氣孔或凹孔皆可經由週遭晶界聚集大量之共晶相蒸氣，引發粗大之黑色凸點。

關鍵字

AA5083 ； 黑色凸點 ； 共晶相蒸發

並列摘要

All the black cauliflower-like precipitates were located on the remelting points and cold shuts of the surface of AA5083 slab. Most of them were composed of several small black precipitates and pores, with MgO and αAl as the major phases. The melting and evaporating of Al-Mg eutectic phases at grain boundaries had to be responsible for this phenomenon. These grain boundaries might be the paths for the evolution of eutectic vapor and give rise to black cauliflower-like precipitates on the surface. Moreover, most gas pores beneath and pits on the original surfaces could be found black cauliflower-like precipitates. Either gas pores or pits could gather considerable eutectic vapor and result in coarse black cauliflower-like precipitates.

並列關鍵字

AA5083 ； Cauliflower-like precipitate ； Evaporation of eutectic