本實驗研究中錳鋼，經冷軋退火程序，探討在不同退火時間與溫度下對於顯微組織及拉伸特性的影響。另外也探討在不同冷軋下，相同退火條件對於鋼材特性是否有影響。實驗發現在25%及50%的冷軋量下，750oC退火10分鐘有約60%最高的延伸率及60 GPa%強延積。不同冷軋量對於相同退火條件沒有明顯的差異。實驗也發現在750oC下退火時間增加，晶粒會成長並傾向等軸發展，合金分佈則有均質化的現象，且當時間達10小時降溫後沃斯田鐵晶粒中會有大量的athermal-麻田散鐵生成。當退火溫度由700oC增加至750oC時間為10分鐘時，沃斯田鐵的相分率會提高，對晶粒大小並沒有明顯影響，沃斯田鐵中的錳濃度會下降，因此降低其穩定性。

This study explores the effect of cold rolling and intercritical annealing on the microstructure and tensile properties of a medium manganese steel. The effects of annealing time and temperature of intercritical annealing have been studied. It was found that cold rolling followed by 750oC annealing for 10 minutes gave the best tensile properties. 25% and 50% cold roll reduction gave similar tensile properties. When the annealing temperature was increased from 700 to 750oC, more equiaxed grains were formed, and the alloy distribution was homogenized. When the annealing time was increased to 10 hours at 750oC, a lot of athermal martensites were formed. Increasing annealing temperature can give higher fraction of austenite, but the manganese content of austenite grains was decreased, so that caused the decrease of austenite stability.

論文審定書 i
中文摘要 ii
英文摘要 iii
圖目錄 viii
表目錄 xx
一、前言 1
二、文獻回顧 2
2-1 TRIP鋼 2
2-2 麻田散鐵 2
2-2-1 麻田散鐵的形成方式 2
2-2-2 麻田散鐵的特徵 3
2-2-3 麻田散鐵的誘發形式 4
2-2-4 麻田散鐵的成核 5
2-3 晶粒尺寸的影響 6
2-3-1 細晶材料的強化 6
2-3-2晶粒尺寸對降伏強度的影響 7
2-3-3 晶粒尺寸對於晶界強化的影響 7
2-3-4 晶粒尺寸對Lu ̈ders應變的影響 8
2-3-5 晶粒尺寸對面積縮減率的影響 9
2-3-6 晶粒尺寸對於沃斯田鐵穩定性的影響 9
2-3-7 晶粒尺寸對於拉伸行為的影響 9
2-4 冷加工的影響 10
2-4-1 冷軋退火過程產生奈米晶結構 10
2-4-2 冷加工對於退火後鋼材沃斯田鐵生成速率的影響 10
2-4-3 冷加工對於沃斯田鐵形貌與分佈的影響 10
2-4-4 冷加工量對於誘發麻田散鐵形貌的影響 11
2-4-5 冷加工量對於二次退火後顯微組織的影響 11
2-4-6 冷加工量對於二次退火後相分率的影響 12
2-4-7 冷加工量對於二次退火後相成分的影響 12
2-4-8 冷加工量對於二次退火後拉伸特性的影響 13
2-5 逆變態沃斯田鐵(ART) 13
2-5-1逆變態與高強度-高延展性鋼 13
2-5-2 逆變態的強化機制 15
2-5-3 冷軋量與退火溫度對於逆變態的影響 15
2-6 退火條件的影響 15
2-6-1 退火溫度的影響 15
2-6-2 退火溫度對於沃斯田鐵成分的影響 16
2-6-3 退火溫度對於晶粒大小的影響 17
2-6-4 退火溫度對Ms溫度的影響 17
2-6-5 退火溫度對於相分率的影響 17
2-6-6 退火溫度對於SFE的影響 18
2-6-7 退火溫度對於機械特性的影響 18
2-6-8 退火時間對晶粒尺寸的影響 19
2-6-9 退火時間對於沃斯田鐵穩定性的影響 20
2-6-10 退火時間對於機械特性的影響 20
2-7 中錳鋼的發展 21
三、研究目的 25
四、實驗方法 26
4-1 實驗材料 26
4-2 實驗步驟 26
4-3 拉伸試驗 26
4-4 顯微組織分析 27
五、實驗結果 29
5-1 熱軋後第一階段高溫熱處理之顯微組織 30
5-2 冷軋後顯微組織 30
5-3 冷軋量25%，相同熱處理溫度750oC，不同熱處理時間(A組) 30
5-3-1 機械特性 30
5-3-2 顯微組織 31
5-3-3 相分率分析 32
5-3-4 元素分析 33
5-3-5 晶粒大小與長寬比 33
5-4 冷軋量50%，相同熱處理溫度750oC，不同熱處理時間(B組) 34
5-4-1 機械特性 34
5-4-2 顯微組織 34
5-4-3 相分率分析 35
5-4-4 元素分析 36
5-4-5 晶粒大小與長寬比 37
5-5 冷軋量25%，不同熱處理溫度，相同熱處理時間10 min(C組) 37
5-5-1 機械特性 37
5-5-2 顯微組織 38
5-5-3 相分率分析 38
5-5-4 元素分析 39
5-5-5 晶粒大小與長寬比 40
5-6 冷軋量25%，750 oC退火5 min其特定應變量組織演化行為(D組) 40
5-6-1 機械特性 40
5-6-2 顯微組織 40
5-6-3 相分率分析 41
5-6-4 元素分析 42
5-6-5 晶粒大小與長寬比 42
六、討論 43
6-1 退火時間的影響 43
退火時間對於相分率的影響 43
退火時間對於顯微組織的影響 44
退火時間對於元素分佈的影響 44
退火時間對於晶粒大小與長寬比的影響 45
退火時間對於拉伸性質的影響 46
6-2 退火溫度的影響 47
退火溫度對於相分率的影響 47
退火溫度對於顯微組織的影響 48
退火溫度對於元素分佈的影響 48
退火溫度對於晶粒大小與長寬比的影響 49
退火溫度對於拉伸性質的影響 49
6-3 拉伸時的組織演化行為 50
七、結論 51
1. 退火時間的影響 51
2. 退火溫度的影響 52
3. 變形組織演化行為 52
八、參考文獻 53

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