多主元合金，也稱為高熵合金，其是一個新的合金設計理念，然而多主元合金的出現改變了我們對於傳統合金的框架和概念，在過去我們所熟悉的傳統合金系統中，幾乎是以一個主要元素為主，再加入若干次要元素以改善其性質，然而多主元合金在這樣多種元素組成下，造就其擁有許多有別於傳統合金的特色和應用，在這一個新興的材料研究領域，多主元合金有更多的研究價值和應用面。
我們利用CALPHAD計算熱力學方法來預測多主元合金的熱處理溫度和相體積分率，本研究以Al-Co-Cr-Fe-Ni五元系統作為研究對象，希望藉由計算熱力學方法輔助探討合金微結構、相體積分率以及機械性質之間的關係，進而設計出兼具高強度與高韌性的新型多主元合金。
根據研究結果顯示，在Al-Co-Cr-Fe-Ni五元系統中，利用CALPHAD計算熱力學方法所得到的溫度及相分率結果與實驗上存在一定的誤差，希望透過在FCC單相中析出B2相和L12相的方式，我們的目標合金可以同時兼具強韌的特性。

Multi-principal element alloys are also called high-entropy alloys, it is a new alloy design concept. However, the emergence of multi-principal element alloys has changed our framework and concept of traditional alloys. In the traditional alloy system that we are familiar with in the past, almost one main element is the main element. Several minor elements are added to improve its properties. However, multi-principal element alloys have many characteristics and applications that are different from traditional alloys under such multiple element composition. In this emerging material research field, multi-principal alloys have more research value and application.
We use CALPHAD computational thermodynamics method to predict the heat treatment temperature and phase volume fraction of multi-principal alloys. In this study, the Al-Co-Cr-Fe-Ni five-element system is used as the research object. It is hoped that the CALPHAD approach can be used to find the relationship between structure, phase volume fraction and mechanical properties, and then design an Al-Co-Cr-Fe-Ni multi-principal alloy with both high strength and high ductility.
According to the research results, in the Al-Co-Cr-Fe-Ni five-element system, the temperature and phase fraction results obtained by the CALPHAD calculation thermodynamic method have certain errors from the experiment. It is hoped that the precipitation with the B2 phase and L12 phase in the FCC single phase, our target alloy can have both strength and ductility properties.

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