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題名 | 半熔融A380鋁合金之攪拌時間對其凝固組織與機械性質的影響 |
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作 者 | 蘇武忠; | 書刊名 | 技術學刊 |
卷期 | 6:1 1991.03[民80.03] |
頁次 | 頁33-42 |
分類號 | 472.5 |
關鍵詞 | 半熔融; 性質; 時間; 組織; 鋁合金; 凝固; 機械; 攪拌; |
語文 | 中文(Chinese) |
中文摘要 | 本文所述乃為半熔融A380鋁合金之攪拌時間對凝固組織與機械性質的影響。以高速轉動的攪拌器置入固液共存區的A380鋁合金中,由於攪拌器轉動的攪拌作業,以致所形成的樹枝狀晶能夠被打斷,而成為非樹枝狀的初晶顆粒,並使合金凝固後能夠獲得晶粒微細化與均質化的組織。將來熔融A380鋁合金進行攪拌而後實施鑄造成形的微觀組織,很受攪拌速率的影響。於低攪拌速率(400rpm )下,初晶顆粒凝聚而成薔薇花之形狀,其分佈不均勻,而且尺寸較為租大;當高攪拌速率(800rpm)時,初晶顆拉的形狀為近似球形,分佈均勻,尺寸亦較細小。本研究乃於合金鑄造成形過程中,結合精速密鑄造、流變鑄造、擠壓鑄造(又稱熔湯鍛造)之方法,而在單純作業中應用二段式高壓來進行加壓,以使其快速凝固成形,因此具有下列之優點:增加模具壽命、晶粒微細化與均質化、改善機械性質、可製造出更細密的鑄件。 |
英文摘要 | The effects of stirring time of partially solidified A380 Al-alloy on the solidification microstructure and mechanical properties had been in-vestigated experimentally and reported in this paper. With a fast-rotating stirrer inserted in the solid-liquid coexisting A380 aluminum melt, the dendrites was broken and formed nondendritic grain nuclei. As the alloy solidified the fine grain and homogeneous microstructure were obtained. The study showed that the as-cast microstructure of the semi-molten A380 aluminum alloy was strongly influenced by the rotating speed. At the low stirring speed (400rpm), the initial grains agglomerated into a cosette shape, and its distribution was not uniform. Besides, the grains were coarser. At the high stirring speed (800 rpm) the form of the grains was nearly spherical and smaller, and the grains were relatively homogeneously distributed. The process was a hybrid metal-forming process which combined acurad casting with rheocasting and squeeze casting in a single operation by applying two-stage high pressure on the casting during solidification. It therefore had the following advantages: longer die life, finer grain and homogeneous micro-structure, improvement on mechanical properties, and production of more dense castings. |
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