2010年美國空軍實驗室提出了數款由 耐火元素組成之 BCC耐火 合 金，如 MoNbTaVW與 HfNbTaTiZr，前者具有很高的密度 ，前者具有很高的密度 但延展性不佳， 延展性不佳， 後者密度較高但延展性表現優異，不過中溫區段易有析出物因此 後者密度較高但延展性表現優異，不過中溫區段易有析出物因此 後者密度較高但延展性表現優異，不過中溫區段易有析出物因此 後者密度較高但延展性表現優異，不過中溫區段易有析出物因此 後者密度較高但延展性表現優異，不過中溫區段易有析出物因此 較容易產生脆性。
於鈦合金當中則是利用析出物強化使度大量提升，並且可以透過 於鈦合金當中則是利用析出物強化使度大量提升，並且可以透過 於鈦合金當中則是利用析出物強化使度大量提升，並且可以透過 於鈦合金當中則是利用析出物強化使度大量提升，並且可以透過 介穩相的成核位置， 適當析出若設計得還可產生變化之現象介穩相的成核位置， 適當析出若設計得還可產生變化之現象介穩相的成核位置， 適當析出若設計得還可產生變化之現象介穩相的成核位置， 適當析出若設計得還可產生變化之現象介穩相的成核位置， 適當析出若設計得還可產生變化之現象介穩相的成核位置， 適當析出若設計得還可產生變化之現象介穩相的成核位置， 適當析出若設計得還可產生變化之現象如形狀記憶合金，使應變硬化能力提升因此在鈦中的強機制是 如形狀記憶合金，使應變硬化能力提升因此在鈦中的強機制是 如形狀記憶合金，使應變硬化能力提升因此在鈦中的強機制是 如形狀記憶合金，使應變硬化能力提升因此在鈦中的強機制是 如形狀記憶合金，使應變硬化能力提升因此在鈦中的強機制是 如形狀記憶合金，使應變硬化能力提升因此在鈦中的強機制是 如形狀記憶合金，使應變硬化能力提升因此在鈦中的強機制是 十分多元且複雜的，但因如此就能有許運用手段及方法。
本研究 由 HfTiZr中熵合金 開始， 開始， 開始， 做適當元素的 添加至 高熵合金 高熵合金 ，利 用滾壓及再 結晶以及時效 處理 ，探討 相轉換 及拉伸性質的關聯 ，提出動 力學 模型 並建立最佳化製程以改進強度 及韌性。可得到抗拉並建立最佳化製程以改進強度 及韌性。可得到抗拉並建立最佳化製程以改進強度 及韌性。可得到抗拉及伸長 率 1085 MPa-3%、900 MPa-9％及 704 MPa-17.5％之合金 。

High-entropy alloys have attracted much attention since 2004. Many kinds of HEAs have been published. Among these, several BCC refractory HEAs were first reported by Senkov and Miracle in 2010. HfNbTaTiZr HEA shows enough strength and good ductility at room temperature. But it suffers brittleness due to the precipitation in 600 Celsius degrees. How to control the precipitation morphology is an important issue.
In contrast to HfNbTaTiZr alloy, titanium alloys can be precipitation hardened to enhance the strength dramatically. The phase transformation can be controlled. Omega precipitates can be utilized as nucleation sites for alpha precipitation to improve the strength and ductility.
This research combines high-entropy alloy’s advantages and titanium’s ones to develop new refractory alloys based on Ti-Zr. Through proper heat treatment, tensile strength-elongation of new alloys could be 1085 MPa-3%、 900 MPa-9％ and 704 MPa-17.5％.

摘 要 I
Abstract II
致 謝 III
目 錄 VII
圖目錄 XII
表目錄 XXIII
壹、 前 言 1
貳、 文獻回顧 3
2.1 傳統合金 3
2.1.1 鈦合金 3
2.1.1.1 α type 鈦合金 5
2.1.1.2 β type 鈦合金 6
2.1.1.3 α-β type 鈦合金 7
2.1.1.4 Metastable β type 鈦合金 10
2.2 高熵合金 13
2.2.1 高熵合金定義 15
2.2.2 高熵四大效應 16
2.2.2.1 高熵效應 (High entropy effect) 16
2.2.2.2 晶格扭曲效應 (Lattice distortion effect) 18
2.2.2.3 遲緩擴散效應 (Sluggish diffusion effect) 21
2.2.2.4 雞尾酒效應 (Cocktail effect) 22
2.2.3 耐火高熵合金 23
2.2.4 常見合金強化機制 26
2.2.4.1 細晶強化 26
2.2.4.2 固溶強化 27
2.2.4.3 析出強化 28
2.2.4.4 相變化強化 30
參、 成分設計與實驗方法 33
3.1 合金設計 33
3.1.1 HfTiZr 33
3.1.2 加入Beta 穩定元素 34
3.1.3 Ti元素為基底元素設計 37
3.2 實驗方法 39
3.2.1 真空電弧熔煉 40
3.2.2 熱處理之微結構觀察與蝕刻條件 40
3.2.3 硬度測量試驗 41
3.2.4 室溫拉伸測試 42
3.2.5 Thermal calc 軟體模擬 43
3.2.6 X-Ray 繞射測試 43
3.2.7 EBSD觀測前處理手續電解拋光: 44
肆、 結果與討論 45
4.1 簡介 45
4.2 第一部分 45
4.2.1 HfTiZr系統基本性質分析 45
4.2.2 HfTiZr加鋁後測試 48
4.2.3 HfTiZr及添加鋁後之比較 52
4.2.4 添加β元素選擇 54
4.2.5 添加5％鈮後之合金 58
4.2.6 添加10％鈮後之合金 65
4.2.7 添加15％鈮後之合金 71
4.2.8 Nb5、Nb10、Nb15三組合金之比較 73
4.2.9 三組合金滾軋後時效機械性質探討 78
4.2.10 三組合金單相小晶粒相分析與機械性質 81
4.2.11 400 ℃小晶粒合金時效後機械性質 92
4.2.12 Nb10 400、450、500 ℃時效後之比較 97
4.2.13 Omega(ω)相之介紹 101
4.2.14 Nb10於450、500 ℃時效一小時機械性質 103
4.2.15 Nb15 500 ℃時效一小時後機械性質 105
4.2.16 Nb10在500 ℃相轉換過程分析及探討 107
4.2.17 Nb10於500 ℃相分析及機械性質 110
4.2.18 Nb10在500 ℃相轉換之微結構形貌與EBSD分析 113
4.2.19 XRD、EBSD、SEM微結構與機械性質歸納比較 123
4.2.20 利用二階時效進一步了解溫度之影響 125
4.2.21 綜合上述之分析動力學模型之建立 132
4.2.22 Nb10 450 ℃ 時效後相分析與機械性質 135
4.2.23 添加鋁於上述合金 138
4.2.24 利用Bo-Md設計出之合金 144
4.2.25 減低鉿之含量 149
4.3 第二部分 153
4.3.1 新型鈦合金的設計及探討 153
伍、 結 論 159
陸、 本研究貢獻 162
柒、 未來研究工作 163
捌、 參考文獻 164

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