多主元合金，亦稱高熵合金，是一種全新的合金概念，它突破了傳統合金中單一種主要元素的框架及限制，採用多個主要元素來組成合金。因具有多種主元的特點，使得多主元合金的微觀組織和性能在許多方面有別于傳統合金。作為一個材料研究的新興領域，多主元合金有著很高的研究價值與廣汎的應用前景。
本研究以Al-Co-Cr-Fe-Ni多主元合金作為研究對象，使用熱力學計算相圖法 (CALPHAD)，通過計算熱力學模擬來預測其相形成，瞭解各元素對成相之影響，並希望藉助計算熱力學模擬的方法來尋找合金成分、相體積分率與機械性質之間的關聯，進而設計出一款兼具強度和韌性的Al-Co-Cr-Fe-Ni多主元合金。
結果顯示，在Al-Co-Cr-Fe-Ni系統中，Co、Ni為FCC相形成元素，Cr為BCC相形成元素，Al為B2相形成元素，Fe為中性元素。CALPHAD可以較為準確地模擬Al-Co-Cr-Fe-Ni多主元合金在凝固過程中發生的反應以及鑄造組織中的相種類，但相體積分率的具體數值與實驗值存在誤差。通過從FCC單相中析出B2相與L12相的方式，目標合金可以兼具良好的強度與韌性，其降伏強度、極限拉伸強度、伸長率分別為470MPa、790MPa、48%，強塑積可達38GPa·%。

Multiprincipal component alloys, also known as high-entropy alloys, are a new concept of alloys that breaks through the limitation of traditional alloy design which is usually based on one or, at most two key elements, and uses multiple principal elements to form alloys. In this study, the Al-Co-Cr-Fe-Ni system was used as the research object. The CALPHAD approach was used to predict the phase formation and understand the impact of each element. It’s hoped that CALPHAD can be used to find the correlation between alloy composition, phase volume fraction and mechanical properties, and design an Al-Co-Cr-Fe-Ni multiprincipal component alloy with high strength and high ductility. The results show that in the Al-Co-Cr-Fe-Ni system, Co and Ni are FCC phase stabilizers, Cr is a BCC phase stabilizer, Al is a B2 phase stabilizer, and Fe is a neutral element. CALPHAD can accurately simulate the reaction of Al-Co-Cr-Fe-Ni multi-principal component alloy during the solidification process and the phase type in the as-cast structure, but the values of volume fraction are inaccurate with the experimental values. By precipitating B2 and L12 from the FCC matrix, the target alloy appears high strength and high ductility, and its YS, UTS and elongation are 470 MPa, 790 MPa, and 48%, respectively.

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