本文旨在探討兩種含鈧、鋯元素之5456鋁合金(M5A；Al - 5.4Mg - 0.1Sc - 0.1Zr；M5B：Al - 6.5Mg - 0.1Sc - 0.1Zr，wt. %)於直接冷卻鑄造法熔煉，再經由熱擠製處理，可獲致機械性質良好之細晶組織。將材料利用不同的冷加工量(軋延)與不同熱處理，探討材料於各階段製程中，退火熱處理的溫度與時間對機械性質的影響。M5A與M5B材經冷加工後，其最佳安定化退火溫度為200 oC持溫60分鐘。
在高溫環境下，其拉伸機械性質亦有優異的表現，探討溫度於200 ~ 500 oC間，應變速率為1 x 10-2 s-1的高速超塑性，其於500oC，最大的伸長率可達1000%以上。
其5456鋁合金經鈧、鋯元素添加後，並配合熱機處理製程，使之具有優異的機械性質，對工業界上的應用有實質上的幫助。

This study investigated the two 5456 aluminum alloys (M5A: Al - 5.4Mg - 0.1Sc - 0.1Zr; M5B: Al - 6.5Mg - 0.1Sc - 0.1Zr, wt. %) that modified by Sc and Zr elements were fabricated by hot extrusion. The studied alloys exhibited an excellent mechanical properties and fine grain structure after vertical direct chill cast (VDC).
The effects of temperature and time on the mechanical properties of the materials were investigated during each stage of the thermo mechanical treatment process with different amounts of cold worked. The best condition of stabilization annealing is 60 minutes at 200 oC after cold worked.
They were also exhibited excellent tensile properties in the higher temperature environment. And the tensile tests were carried out at temperature of 200 to 500 oC and strain rate of 1 x 10-2 s-1. The maximum elongation to failure of ~1000 % was obtained at the strain rate of 500 oC and 1 x 10-2 s-1.
The 5456 aluminum alloys modified by Sc and Zr elements with thermo mechanical treatment process exhibited excellent mechanical properties for high strength weld structure applications. The two alloys were useful and helpful for industry-wide practical applications.

目　　　錄
中文摘要 i
英文摘要 ii
誌謝 iii
目錄 iv
表目錄 vii
圖目錄 viii
第一章 前言 1
第二章 文獻回顧 4
2-1 強化機構 4
(1) 固溶強化 4
(2) 散佈強化 5
(3) 應變硬化 7
2-2 退火熱處理(回復、再結晶、晶粒成長) 8
2-3 時效軟化 9
2-4 超塑性簡介 9
2-5 鋁鎂合金超塑性 13
(1) 熱機處理 13
(2) 合金元素添加 14
第三章 實驗方法 20
3-1 實驗材料 20
3-2 實驗流程 20
3-3 退火熱處理 20
(1) 退火熱處理 21
(2) 加工後退火熱處理(安定化、部份退火) 21
(3) 多段次退火熱處理 21
3-4 冷軋延 22
3-5 示差掃描熱分析 22
3-6 超塑性實驗 23
(1) 等應變速率不同溫度之超塑性實驗 23
(2) 試片經熱機處理後中低溫高速超塑性實驗 23
(3) 等溫度不同應變速率之超塑性實驗 24
3-7 常溫拉伸實驗 24
3-8 金相觀察 25
3-9 掃描式電子顯微鏡觀察 25
3-10 穿透式電子顯微鏡觀察 25
3-11 微硬度實驗 26
第四章 結果與討論 32
4-1 鑄錠經熱擠製後顯微結構的變化 32
4-2 退火熱處理 33
4-3 拉伸破斷面之觀察 34
4-4 加工硬化及加工後熱處理 35
4-4-1 不同軋延量之試片比較 35
4-4-2 加工後退火熱處理 36
4-4-3 穿透式電子顯微鏡觀察 39
4-4-4 多段次軋延及退火熱處理 40
4-5 鋁鎂合金超塑性特性 41
4-5-1 等應變速率不同溫度之超塑性 41
4-5-2 試片經熱機處理後中低溫高速超塑性實驗 44
4-5-3 等溫度不同應變速率之超塑性 45
第五章 結論 119
第六章 未來研究方向 122
參考文獻 123

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