本論文研究鐵錳合金鋼中次微米沃斯田鐵晶粒經應變後產生的應變誘發麻田散鐵之成核組織。本論文利用SEM及EBSD研究麻田散鐵之成核位置及其與母相沃斯田鐵的結晶方位關係並研究成核所在之沃斯田鐵晶粒及鄰近肥粒鐵晶粒的晶粒大小、晶粒形狀、Schmid factor之大小以了解成核所需之條件。實驗結果發現單一麻田散鐵晶粒與母相沃斯田鐵晶粒間在不同界面位置可以有K-S、G-T及N-W OR三種晶向關係。在次微米沃斯田鐵晶粒中應變誘發麻田散鐵是在沃斯田鐵與肥粒鐵的兩相界面處成核，與大晶粒在晶粒內成核位置不同。麻田散鐵成核之所在位置之沃斯田鐵其Schmid factor較其他沃斯田鐵晶粒大，且其尺寸也較大。沃斯田鐵晶粒之形狀則對成核無明顯的影響。

This research investigated the nucleation of strain-induced martensite from submicron-grained austenite of a medium manganese steel. Scanning electron microscopy and electron backscattered diffraction were used to study the nucleation site of martensite, and the orientation relationship between martensite and austenite. Grain size, shape, and Schmid factor of austenite grains where martensite nucleated, and ferrite grains which close to the nucleated martensite were measured. It was found that in submicron-grained austenite, martensite is nucleated at the interphase boundary of austenite and ferrite, which is different from austenite having ordinary grain size, in which martensite is nucleated from grain interiors. The orientation relationship between martensite and austenite was found varied in locations, K-S, G-T and N-W orientation relationships were found. Large Schmid factor and grain size are the favor factors for the nucleation martensite.

目錄
一、 前言 1
二、文獻回顧 2
2-1 塑性變形誘發麻田散鐵相變化（Transformation Induced plasticity ,TRIP)鋼 2
2-2 麻田散鐵及其特徵 2
2-3 bcc結構與fcc結構之間的結晶方向關係 6
2-4 麻田散鐵成核位置之觀察 13
2-5 沃斯田鐵晶粒尺寸效應 16
三、研究目的 20
四、實驗方法 21
4-1 實驗材料 21
4-2 拉伸實驗 21
4-3 顯微組織觀察 21
4-4 背向散射電子繞射分析 22
五、實驗結果 23
5-1 拉伸後的顯微組織 23
5-2 麻田散鐵成長初期與母相沃斯田鐵間的結晶方位關係 24
5-3 母相沃斯田鐵晶粒的Schmids factor分佈 25
5-4 與α’麻田散鐵相鄰之bcc肥粒鐵的Schmids factor 27
5-5 沃斯田鐵與α’麻田散鐵晶粒內的晶向gradient 28
5-6 鄰近肥粒鐵與α’麻田散鐵之間的misorientation 28
5-7 母相沃斯田鐵與相鄰肥粒鐵之間的misorientation 29
5-8 麻田散鐵鄰近肥粒鐵的晶粒尺寸和形狀分析 29
5-9 母相沃斯田鐵的晶粒尺寸和形狀與α’麻田散鐵成長之間的關係 30
六、討論 32
6-1 α’麻田散鐵與母相沃斯田鐵的結晶方位關係 32
6-2 α’麻田散鐵的成核位置 35
6-2-1晶粒之間的Misorientation對α’麻田散鐵成核位置影響 36
6-2-2晶粒尺寸與形狀對α’麻田散鐵成核位置的影響 37
6-2-3 Schmid factor與α’麻田散鐵的成核位置的關係 38
七、結論 40
八、參考文獻 41

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