由Wang等人對純銅在低溫下作軋壓並退火後觀察的結果發現，當奈米結晶基材內部混著微米晶粒，而形成所謂的bimodal晶粒分佈時，不但能提升材料的強度，同時也可維持材料的延展性。本實驗將研究純鎳是否也有類似的行為，並量測在液態氮溫度及室溫下給予95%的軋壓量後，在不同退火條件下的硬度值及應力-應變，並觀察商用鎳在低溫及室溫下的微觀組織及微觀參數。
觀測的結果發現商用鎳及電鍍鎳在經過液態氮溫度下軋壓後且在不同的退火條件下作退火，當延展性上升時，則強度下降，並無Wang等人所提出的可提升材料強度同時也可維持材料延展性的結果，因此推測bimodal結構並不適用於所有機械；而低溫軋壓對於純鎳微觀組織的影響為使得LBs間距變的較小，但LBs晶向差則無太大的改變。

Wang etc. find that when abnormal grain growth has volume fraction of 25% of coarser grain (bimodal structure), the material can exhibit high strength and high tensile ductility. We will find that if Ni has the same properties.
The conclusion show that after 95% reduction at liguid nitrogen temperature and under different annealing temperature, when strength growth, then tensile ductility down. And we also measure hardness, stress-strain curve,and morphology after 95% reduction in Ni.And LBs spacing is closer, LBs misorientation is not variation a lot when rolling at low temperature then in room temperature.

壹 前言 1
貳 文獻回顧 2
2-1 大量塑性變形 2
2-2 回復與再結晶 2
2-2-1 回復 2
2-2-2 再結晶 3
2-2-3 影響再結晶的因素 3
2-3 晶粒尺寸對材料強度的影響 3
2-3-1奈米結構金屬的拉伸延展性 3
2-3-2純鎳中晶粒尺寸對加工硬化的影響 6
2-4冷加工後的微觀組織 7
2-4-1 鋁經軋壓後的微觀組織 7
2-4-2純鎳在低變形量時的微觀結構 10
2-4-3 純鎳在中至高變形量時的微觀結構 11
2-5 微觀組織參數與強度間的關係 14
2-5-1純鎳在高變形量時的微觀結構與強度間的關係 14
2-5-2 差排晶向差與材料強度間的關係 15
2-6 變形組織參數機率分佈曲線的正規化(scaling) 17
2-6-1 差排牆晶向差正規化後的函數分佈曲線 17
2-6-2 差排牆間距正規化後的函數分佈曲線 19
參 研究目的 20
肆 實驗方法 21
4-1 材料之準備 21
4-2 實驗步驟 21
4-2-1 低溫軋壓 21
4-2-2退火處理 21
4-2-3 微硬度測試 21
4-2-4 金相試片製作 22
4-2-5 拉伸試驗 22
4-2-6 TEM試片製作 22
4-2-7 LBs晶向差的量測 23
4-2-8 LBs間距的量測 24
4-2-9 scaling化的原理與過程 24
伍 實驗結果 26
5-1 不同退火條件下的硬度值與金相觀察 26
5-2 材料強度 26
5-3 穿透式電子顯微鏡的觀察 27
5-3-1 商用鎳及電鍍鎳的形態學 27
5-3-2 LBs的晶向差 27
5-3-3 LBs的間距 28
5-3-4 商用鎳LBs間距之scaling 28
5-3-5 高用鎳的再結晶組織 29
陸 討論 30
柒 結論 34
捌 參考文獻 35
附錄 TEM圖號 99

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