目前為止，合金設計以及合金選擇之理念仍未脫離以一種元素或化合物為主的觀念；有鑑於前述傳統合金設計理念顯然限制了合金成分的自由度，因而可能限制特殊微結構及性能的發展，於是新的設計觀念被提出以突破傳統上的限制。在此新觀念下設計的合金“多元合金“組成基本上無主要元素。
噴覆成型製程(SFP)具有快速凝固之特性，故經由此製程所製得之材料具有晶粒尺寸小、減少偏析等特性；本研究主要以銅、鈷、鎳、鉻、鋁及鐵六種不同元素組成的多元合金為實驗材料。比較由傳統鑄造與噴覆成型製程對材料之微結構與機械性質之影響。研究結果鑄造材的晶粒大小為270∼1000μm且結構為樹枝狀結構，而噴覆材晶粒大小為2∼7μm，結構為細小的球狀晶粒，不僅大大的細化了晶粒尺寸同時也減少了銅元素的偏析情形。
機械性質部分，噴覆材與鑄造材多元合金在高溫下具有相當良好的強度，強度可維持到1000℃以上，無論巨觀硬度(HRC)或是微觀硬度(MHv)皆與室溫下幾乎相同，在1050℃持溫12小時後噴覆材與鑄造材的硬度皆有明顯下降且鑄造材下降幅度皆大於噴覆材，鑄造材微觀硬度(MHv)甚至低於噴覆材，因此噴覆材高溫穩定性質較佳。三點抗折試驗部分，觀察其破斷面微結構，發現噴覆材晶粒內部有許多韌窩(dimple)結構，鑄造材破斷面則沿著樹枝間偏析處產生裂縫，其破斷面屬於脆性破斷，兩者的破斷應力皆為370kgf，計算其破斷韌性值，噴覆材為256.8kgf-mm、鑄造材為70.3kgf-mm，結果顯示噴覆材的韌性較鑄造材高，約為鑄造材的3.6倍。

In tradition, the development of an alloy system is almost based on a major element. It will limit the freedom to design alloys、microstructures and properties. Therefore ,the 6-component alloy system is expected to break the conventional design.
The alloys with reduced grain size and less segregation can be produced via the spray forming process, in which rapid solidification condition is achieved. The high entropy alloy used in this study consists of six elements, including Cu, Co, Ni, Cr, Al and Fe. The influence of process parameters on microstructure and mechanical properties of either the as-spray-formed or the as-cast billets were also studied. The grain size of as-spray-formed billet was reduced to 2-7 μm with round shape, while the grain size of conventional as-cast billet was about 270-1000 μm with dendritic structure. Therefore, spray forming process can not only refine the structure but also eliminate the segregation of copper element found in the as-cast one.

目錄
表目錄
圖目錄
中文摘要 1
英文摘要 2
第一章 序論 4
第二章 基礎理論 8
2.1 非晶質合金發展與應用 8
2.2 非晶質合金製程 10
2.3 非晶質合金的優異特性 11
2.4 非晶質合金形成理論 12
2.5 影響非晶質合金形成因素 13
2.5.1 玻璃形成能力 13
2.5.2 冷卻速率 14
2.5.3 合金原子間的鍵結特性與晶體
結構特性14
2.5.4 約化玻璃轉換溫度 15
2.5.5 共晶成分 15
2.6 多元合金發展 16
2.7 噴覆成型製程理論 18
第三章 實驗方法 22
3.1 實驗目的 22
3.2 實驗材料 22
3.3 實驗流程 23
3.4 噴覆成型多元合金 24
3.5 實驗分析 25
3.5.1 多元合金之微觀組織分析 25
3.5.2 結晶結構分析 27
3.5.3 巨觀成分分析 27
3.5.4 熱性質分析 27
3.5.5 機械性質分析 28
3.5.6 其它分析及設備 29
第四章 實驗結果與討論 30
4.1 製程參數優劣對SFP billet 的影響 30
4.2 噴覆成型與傳統鑄造製程顯微結構與相結構分析 31
4.3 機械性質分析 40
4.3.1 硬度測試分析 40
4.3.2 高溫穩定性 44
4.3.3 三點抗折之破斷面分析 46
第五章 結論 49
第六章 參考文獻 51

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