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    請使用永久網址來引用或連結此文件: http://ir.lib.ncku.edu.tw/handle/987654321/76896


    題名: 高強度沃斯回火球墨鑄鐵(ADI) 之高溫變形特性及組織解析研究
    其他題名: Studies of the Deformation Behavior and Microstructure on Austempered Ductile Iron at Elevated Temperature
    作者: 呂傳盛
    貢獻者: 材料科學及工程學系
    關鍵詞: 沃斯回火
    球墨鑄鐵
    高溫性質
    脆化
    動態應變時效
    球墨粒徑
    矽含量
    Austempering
    Nodular graphite cast iron
    High temperature property
    Embrittlement
    Dynamic strain aging
    Graphite size
    Silicon content
    日期: 1994
    上傳時間: 2009-09-15 09:24:59 (UTC+8)
    摘要: 本計畫以三種矽含量(2.4%、2.9%、3.3%)的ADI材料為研究對象,2.4Si與3.3Si之ADI試件則有兩種不同的球墨粒徑;因此,自本研究的實驗結果可得知矽含量與球墨粒徑對其高溫特性的影響。如實驗結果所述,ADI的高溫變形特性約可區分為兩個溫度區間。第一段溫區約在室溫至300.degree.C之間,此段溫區的高溫變形特性與動態應變時效的現象有關。造成ADI動態應變時效現象的原因與其組織中針狀肥粒鐵的作用有關,此時ADI組織中差排密度的高低會影響其流變不穩定的現象。第二段溫區約在300.degree.C至500.degree.C之間,造成此段溫區之變形特性的原因,應與碳化物的作用有關。另外,當ADI的矽含量升高時,其流應力有增高的情形,但其延伸率則有降低的現象;其原因應與矽含量較高時,鑄造缺陷亦會隨之而增多現象有關。而當ADI的球墨粒徑較小時,其延伸率與流應力均有增高的情形,造成此現象的原因應與ADI組織變為較細密的情形有關。
    Three ADI specimens with silicon contents of 2.4, 2.9 and 3.3 in wt% were used in this program. The effect of graphite size on the features of ADI were also used in specimens with 2.4wt%Si and 3.3wt%Si. As a consequence, the effect of silicon and graphite size on the features of ADI should be studied. As revealed in experimental results and discussions, the features of ADI are divided into two temperature regimes. In the first regime, at about R.T. to 300, the feature is due to the dynamic strain aging. The cause of dynamic strain aging is attributed to the acicular ferrite and the dislocation density in ADI microstructure should play an important role on the occurrence of flow instability. The second regime is at about 300.degree.C to 500.degree.C, the feature is due to the effect of carbide. Otherwise, the flow stress increases and elongation decreases as the content of silicon increases. This effect of silicon addition on the mechanical properties is attributed to the more casting defects with high silicon content. Another results indicate that the flow stress and elongation both increase with smaller graphite size. The finer microstructure of ADI is the reason for this effect of graphite.
    相關連結: http://grbsearch.stpi.narl.org.tw/GRB_Search/grb/show_report.jsp?projkey=PA8301-2245
    描述: 計畫編號:NSC83-0405-E006-007
    執行機構:成功大學材料科學及工程學系(所)
    研究期間:1993-08~1994-07
    顯示於類別:[材料科學及工程學系] 國科會研究報告

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