近幾十年來，多元金屬玻璃(multi-component glassy metal)由於具有一些優越獨特的物理特性及化學特性，已引起世界眾多學者的廣大興趣。在熱力學上，非晶質相一直被認為是一個不穩定相(unstable phase)，因此在高溫熱處理下，其微結構將會逐漸改變為較穩定的結晶相。由於材料之結構和其物理性質息息相關，了解金屬玻璃結構改變機制以及其對材料物理性質的影響，是一有趣且重要問題。本論文即對這方面做了一系列的研究。
本實驗採用嶄新的合金設計概念--高熵合金，設計出ZrTaTiNbSi合金靶材，再利用直流磁控濺鍍，成功地鍍製出5元高熵合金的非晶質ZrTaTiNbSi合金薄膜。所鍍製出的薄膜採石英真空封管的方式，分別在473、573、673、773、873、973、1073及1173 K熱處理10分鐘。而後採用X光繞射分析與高解像穿透式電子顯微鏡分析作微結構分析，同時利用四點探針法量測電阻率，以及利用奈米壓痕法測量薄膜硬度。
從X-ray的繞射分析，經過不同溫度(473 K-1173 K)10分鐘熱處理後，其薄膜微結構不但保持非晶狀態，而且非晶質的峰值顯示溫度愈高，非晶質愈趨於無序化，與傳統觀察相反。同時，薄膜之電阻率從115 μΩ-cm(300 K，初鍍膜)提高4倍左右至432 μΩ-cm (1173 K退火10分鐘)。硬度也從2.29 GPa(300 K，初鍍膜)提高5倍左右至11.60 GPa (1173 K退火10分鐘)。從HR-TEM繞射圖形經傅立葉轉換的〝全約徑向分布函數〞(RDF)分析，可以清楚看到薄膜中第一配位數原子間距離趨向更大的分佈範圍，但實際上為兩種分佈所重疊，由於M’-Si鍵結長度為0.247 nm (M’=Zr, Ta, Ti, Nb)與M-M鍵結長度為0.300 nm(M=Zr, Ta, Ti, Nb, Si)，分別與兩分佈中心相符合，所以我們推測在退火中，矽原子與其他金屬原子產生某種程度的聚集現象，但仍維持非晶質狀態。也就是原子在鍵結上發生了改變，更大的無序化現象主要是來自金屬鍵結模式逐漸轉變成金屬鍵結加共價鍵結模式，使鍵結長度有更大的分佈範圍。對於此一非傳統現象，本研究利用自由能的計算，發現高熵效應在此無序化現象中扮演重要的角色。此外，根據此一微結構演變，我們可以成功地解釋XRD曲線、電阻率及硬度，隨退火溫度非傳統性改變的現象。

In this work, Zr17Ta16Ti19Nb22Si26 amorphous thin films have been prepared from high entropy alloy target of the same composition. The derived films were subsequently annealed at various temperatures from 473 K to 1173 K for 10 minutes. X-ray diffraction results indicated that the films remained in amorphous form. Nevertheless, the amorphous scattering peak became more diffuse as the annealing temperature increased, suggesting the increase of degree of disorder with the annealing temperature. In addition, resistivity and hardness of films were also found to increase with annealing temperature. From the reduced density function, the metal-Si bonding was found to change gradually in the annealing process. In the as-deposited film, Si atoms stayed as solutes in the alloy matrix, whereas metal-Si bonding was more silicide like in the film subjected to 1173 K-anneal. The gradual formation of silicide-like bonding might cause the atomic spacing to split into two distinct lengths, lower the free electron density, enhance the electronic scattering, and bonding strength of amorphous films. This explained the more diffuse scattering peaks of XRD, and the increase of resistivity and hardness of post-annealed films.

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