臺灣博碩士論文加值系統

　　本實驗主要研究如何以噴覆成型的方式噴覆出性質優良的6061鋁合金。於噴覆出符合要求的6061鋁合金圓錠之後，將分析噴覆成型6061鋁合金與一般商用連續鑄造6061鋁合金之顯微結構；同時進行實驗比較其擠型性質，以及使用理論模式評估擠型峰值壓力並與實際實驗所得做一比較；在機械性質方面將測試兩種製程的T6熱處理硬度以及常溫拉伸強度。分析結果顯示噴覆成型6061鋁合金具有均勻一致的微細晶粒以及分布均勻的細微析出物；而連續鑄造鋁合金則有析出物偏析於晶界以及晶粒大小不均勻的顯微結構。於擠型性質方面，噴覆成型鋁合金具有較為寬廣的操作區間以及於相同操作條件下較低的擠型峰值壓力；所得的擠型壓力峰值與理論預測值也相當符合。在硬度以及拉伸強度的材料機械性質方面，噴覆成型鋁合金亦展現了較高的硬度與優秀的拉伸強度，不過延性方面則因為強度的提升而降低。

　　The thesis mainly focused on how to obtain an spray-formed AA6061 billet with superior properties than as-cast one. The spray forming process is asked that the porosity of the billet must be controlled below 2% . Moreover we analyzed and compared the microstructure and mechanical properties with the commercial continuously cast ones. The obtained as-spray-formed AA6061 billet consisted of uniform grain size and fine、well-distributed precipitates at grain boundary. On the other hand, the as-cast AA6061 equipped with non-uniform grain size and the precipitates segregate mainly at grain boundary. The workability of as-spray-formed AA6061 billet is better than the as-cast ones and can be extruded with lower peak pressure. We also use the upper bound theory proposed by Sheppard and his partners to predict the peak pressure and get a reasonable assessment that the experimental peak pressure is below the predict one at 400℃-480℃. The hardness measured after T6 heat treatment also show that as-spray-formed AA6061 with higher hardness about HRB 62. In tensile test, the as-spray-formed AA6061 alloy showed higher YS and UTS but lower ductility than as-cast ones.

摘要 I
Abstract II
第一章、前言 1
第二章、實驗理論基礎 2
2-1噴覆成型理論 2
2-2 金屬機械加工性質理論 4
2-2-1 熱加工 4
2-2-2拉伸測試原理： 5
2-3 鋁-鎂-矽三元合金相圖 6
2.4 合金成分對於機械性質的影響 7
2-5 析出物的種類與型態 8
2-6 擠型性與擠型極限圖 9
2-7 Zener factor與流變應力以及擠型壓力的評估 11
2-7-1 Zener factor與流變應力 11
2-7-2 擠型壓力的評估 13
2-8 影響峰值擠型壓力的因素 15
2-8-1 溫度對流變應力的影響 15
2-8-2 應變速率的影響 16
2-8-3晶粒大小的影響： 16
2-8-4 析出物的影響： 17
第三章、研究動機及實驗方法 18
3-1研究動機與目的 18
3-2 實驗材料 18
3-3 噴覆成形製程 18
3-4 噴覆成型材料析出相鑑定與顯微組織分析 19
3-5 Thermo calc. 預測分析 19
3-6 擠型實驗 20
3-7 硬度試驗 20
3-8 拉伸測試 21
第四章、結果與討論 22
4-1 噴覆成型實驗 22
4-2 噴覆成型與連續鑄造6061鋁合金其顯微結構與成分分析 23
4-2-1 X-ray分析結果 23
4-2-2 金相分析結果 24
4-2-3 SEM分析與EDS成分分析及相鑑定 24
4-2-4 thermo calc. 預測與分析 26
4-3 擠型實驗分析 27
4-3-1 1：10擠型比分析 27
4-3-2 1：25擠型比分析 31
4-4 擠型壓力的評估 33
4-5 硬度測試 36
4-6 拉伸試驗 38
第五章、結論 41
第六章、參考文獻 43

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