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題 名 | Ni[feb0]Al介金屬合金之高溫流應力特性研究 |
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作 者 | 黃正穎; 曹申; 杜經邦; 蔡忠城; 闕山璋; | 書刊名 | 材料科學 |
卷 期 | 25:4 1993.12[民82.12] |
頁 次 | 頁332-335 |
分類號 | 440.39 |
關鍵詞 | 介金屬合金; 熱壓縮; 流應力; 流軟化; 蝸形應變; 動態再結晶; 初始熔解; Intermetallic alloy; Hot compression; Flow stress; Flow softening; Stretcher strain; Dynamic recrystallization; Incipient melting; |
語 文 | 中文(Chinese) |
中文摘要 | 目前Ni�蚊1基介金屬合金之商業化量產技術尚未成熟發展,尤其是熱加 工特性方面之探討仍很缺乏。本研究以Gleeble-2000 AA熱加工模擬機對 Ni-9.44A1-7.79Cr-0.19Zr-0.02B(wt.)合金作熱壓縮試驗,並由光學顯微鏡觀察顯微 組織的變化,以探討此類合金之熱加工特性。實驗結果顯示,壓縮流應力隨溫度 之降低及應變速率之提高而急劇變大。在0.01S�笐謊傅亶t率下熱壓、淬火後之 試片顯微組織觀察顯示,熱加工特性測試過程中造成流應力下降之軟化變形機 構,在800℃時主要為非均勻蝸形應變;1000℃時為原始晶界附近之動態再結 晶;1200℃時除了有明顯項鍊狀動態再結晶之外,滑移帶生成仍是主要機構;然 而,1250℃時動態再結晶現象更加明顯,但此溫度下樹枝間較低熔點區域之初始 熔解亦足以促使流應力下降,造成沿晶破裂。 |
英文摘要 | The commercial manufacturing processes of Ni�蚊l-based inter metallic alloys have been underdevelopment; especially, the complete idata base of hot forming characteristics is still lacking. In this paper, the hot workability of a Ni-9.44Al-7.79Cr-0.19Zr-0.02B (wt.) alloy was investigated by Gleeble2000AA hot compression tests and micro structural observations. The experimental results showed that the flow stress increased rapidly with decreasing temperature and increasing strain rate. The microstructures of hot deformed (ε =0.01 s�笐�) and water quenched specimens were examined by optical micros copy, and the flow softening mechanisms varied at different hot compression temperatures. At 800℃, the formation of non-uniform stretcher strains played a major role. At 1000℃, the dynamic recrystallization near original grain boundaries became dominant. At 1200℃, in addition to the necklace-structure of dynamic recrystallization, the slip band formation was also important. However, at 1250℃, the dynamicrecrystallization structure was more prominent, but the incipient melting of the lower melting pointinter-dendritic regions could cause the flow stress reduction and the intergranular fracture at this temperature. |
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