本論文研究中錳鋼材在10-5/s應變速率下拉伸溫度對拉伸性質與顯微組織的影響。實驗發現常溫下應變誘發麻田散鐵主導變形機制，使試片有最大的拉伸強度。在75℃時應變誘發麻田散鐵受到溫度效應抑制，此時變形誘發變韌鐵開始形成但仍不明顯，變韌鐵出現的數量不足以彌補麻田散鐵下降的數量使拉伸強度略為下降。拉伸溫度在150℃時有最多的變形誘發變韌鐵相轉換，使得拉伸強上升至室溫的拉伸強度。在75℃到150℃間因沃斯田鐵穩定度上升，使變形誘發麻田散鐵數量下降，但變形誘發變韌鐵的數量上升而有助於加工硬化，所以使伸長量上升至75%左右。在150℃與200℃之間變形誘發變韌鐵相轉換數量下降，拉伸強度也隨之微幅下降。在225℃以上變形誘發肥粒鐵主導變形機制，此時強度和伸長量皆隨溫度上升而明顯下降。

This study explores the effect of test temperature on tensile properties and microstructure of a medium Mn steel under low strain rate (10-5 per second). It was found that the maximum tensile strength at room temperature is mainly caused by strain-induced martensite transformation. Above 75℃, strain-induced martensite was suppressed with increasing temperature, and deformation induced banite occurred in austenite. It was close to the tensile strength under room temperature at 150℃ because of the most deformation induced banite transformation volume fraction. The elongation increased to 75% between 75℃ and 150℃, because both slow TRIP effect and increasing banite transformation provided work hardening. Between 150℃ and 200℃, volume fraction of deformation induced banite deceased, and tensile strength also decreased slightly. Up to 225℃, mechanical properties was controlled by deformation induced ferrite transformation, and strength and elongation decreased with increasing temperature.

論文審定書 i
中文摘要 ii
英文摘要 iii
目錄 iv
圖目錄 vi
表目錄 xiii
一、前言 1
二、文獻回顧 2
2-1 麻田散鐵 2
2-1-1 麻田散鐵相轉換機制 2
2-1-2 麻田散鐵的形貌 3
2-1-3 麻田散鐵的成核 4
2-2 沃斯田鐵的穩定性 5
2-3 TRIP效應 7
2-4 應變速率對TRIP效應的影響 8
2-5 溫度對TRIP效應的影響 11
2-6 變形誘發變韌鐵相轉換(Deformation Induced Bainite,DIB) 13
三、研究目的 14
四、實驗方法 15
4-1 實驗材料 15
4-2 表面處理 15
4-3 拉伸試驗 15
4-4 顯微組織觀察 15
4-5 X光繞射分析 16
4-6 EBSD分析 16
五、實驗結果 17
5-1 機械性質 17
5-2 相分率 19
5-3 顯微結構觀察及EBSD分析 20
5-3-1 在四個不同拉伸溫度下未受拉伸變形之夾頭端組織 20
5-3-2 在不同溫度下受拉伸變形gauge區域之顯微組織 21
5-4在150℃不同應變量之拉伸組織 26
5-4-1 相分率比較 26
5-4-2 顯微組織觀察及EBSD分析 26
六、討論 28
6-1顯微組織的演化 28
6-2 拉伸性質 29
七、結論 32
八、參考文獻 33

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