本研究主要針對高熵合金中四大核心效應：高熵效應、雞尾酒效應、嚴重晶格扭曲效應和遲緩擴散效應中的後二者效應，以目前較少研究的介金屬析出相為材料進行探討，研究分為兩大主題，高熵合金系統中σ相的元素序化及晶格扭曲和γ’相的析出動力學。
在第一部份的研究中，我們透過不同的研究方法計算出不同物理意義上的晶格扭曲量值，分別為：系統內元素成分尺寸的標準差(δ)≈9.9 % 、實際與標準狀態下的晶格常數差異(ε)≈2.74 %、利用Williamson-Hall方程式計算出的微觀應變(ε_WH)≈9.2 %以及原子影像內各晶格常數間的變異係數(CV)≈3 %。並且透過Cs-STEM的高解析原子影像證實高熵合金系統的介金屬σ相與一般二元合金相比有較大的晶格扭曲量及較低的序化程度。此外，透過原子級的EELS mapping，我們發現高熵合金系統σ相晶格中元素的佔據模式與以往σ相的AB類元素佔據方式有所不同。
第二部分的研究我們發現透過調整高熵合金Cu的含量，能使合金的析出行為產生變化。Cu的加入使析出物粗化的反應速率、活化能及析出物尺寸增加，不過會小幅的降低析出物密度與析出物總體積分率。得到的結果顯示此合金與Ni基合金相比有明顯較低的析出物粗化速率以及較高的活化能，驗證高熵合金中的遲緩擴散效應。

This study focuses on two of core effects of high-entropy alloys (HEAs): the severe lattice distortion and the sluggish diffusion. We concentrate in the discussion of the intermetallic precipitation phases, and the study can be divided into two parts based on different HEA systems, namely: elemental ordering and lattice distortion of σ phase and the precipitation kinetics of the γ' phase.
In first part, we extracted the lattice distortion values of σ phase in HEA through different approaches, the standard deviation of the atom size in the system (δ) ≈ 9.9 %, the difference of lattice constant between experimental and theoretical states (ε) ≈ 2.74 %, and the microscopic strains calculated by the Williamson-Hall equation (ε_WH) ≈ 9.2 %, and the coefficient of variation (CV) ≈ 3% between the lattice constants calculates from atomic image. According to the atomic STEM image, it is confirmed that the intermetallic σ phase in the HEA system has larger lattice distortion and lower degree of ordering compared with the conventional binary alloy system. Besides, through atomic EELS mapping, we found that the occupant possibility of the elements in the σ phase of the HEA system is different from that in the conventional binary alloy system.
In the second part of the study, we found that the precipitation behavior of the alloy can be changed by adjusting the content of Cu in HEA system. The coarsening rate (K), activation energy (Q) and precipitate size (d) increase with the addition of Cu, nevertheless, the precipitate density (Nv) and total volume ratio of the precipitate (ϕ) are also slightly decreased. The calculated results show that these HEAs has the significantly lower precipitation coarsening rate and higher activation energy than other Ni-based alloy, which verifies the sluggish diffusion effect in the HEA system.

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