本論文以分子動力學 (MD) 模擬薄膜之濺鍍沉積所製備出的鋯基金屬玻璃薄膜(Zr47Cu31Al13Ni9)，此薄膜的力學性質則由奈米壓印模擬進行探討。在沉積模擬中，多種原子與原子間的交互作用力採用了tight-binding (TB) 多體勢能，金屬原子與作用氣體 (Ar+) 間作用力使用Moliere 勢能。沉積模擬結果顯示此薄膜為一非晶系統。接著利用圓錐探針進行壓痕模擬，並在金屬玻璃的表面觀察到，均勻塑性流動堆積的現象。且從MD計算的堆積指標與實驗結果是可以相互比較的。而且，我們的MD結果指出，堆積指標在玻璃轉換溫度附近，顯示不正常跳躍現象，可以間接解釋此薄膜的玻璃轉換溫度為758K。本文進而由壓印模擬中的力與位移關係，隨著溫度的改變，探討壓痕模數以及硬度與溫度的關係圖，MD模擬與實驗結果在硬度與楊氏模數隨時間減少的速率是一致的。常溫300K中硬度實驗是5.2GPa，MD模擬是7GPa，硬度隨溫度改變速率約2MPa/K；而楊氏模數實驗為80GPa而MD模擬僅為40GPa，楊氏模數隨溫度改變速率為22MPa/K。金屬玻璃的變形機制為剪力帶的形成與傳遞，此機制亦控制金屬玻璃的機械性質。本文由三維空間原子尺度下的應變間接探討剪力帶的形成與分佈，並且研究探針尖端下的局部應變與剪力帶的關係。另外，更快的壓印速率會降低硬度，並且在凹痕尖端產生更大的擾動區域及擴大剪力帶範圍。

Molecular-dynamics (MD) models of the Zr-based metallic-glass film (Zr47Cu31Al13Ni9, in atomic percent) were constructed via simulating sputter depositions. The as-deposited films were used as initial structures for subsequent nano-indentation simulations. For the deposition simulations, a many-body, tight-binding potential was adopted for interatomic interactions among the multiple species of atoms. Interactions between the metallic atoms and working gas (Ar+) were modeled with the pair-wise Moliere potential. The deposition simulations revealed an amorphous morphology of the as-deposited films. Indentation simulations with a right-angle conical indenter tip showed a homogeneous flow to form pile-ups on the surface of the metallic glass around the indent. The pileup index calculated from MD is consistent with that obtained from the experiment. Moreover, our MD results show that the pileup index exhibits anomalies, defined as unusual changes in the values of the pileup index, around the glass-transformation temperature (758 K) through in situ indentation simulations. From indentation load-displacement curves at various temperatures, it is found that indentation modulus and hardness obtained from MD simulations are in agreement with experimental findings in terms of their decreasing rates with respect to the temperature. The hardness in experiment is 5.2GPa and in MD simulation is 7GPa. The decreasing rate of hardness is about 2MPa/K. The Young’s modulus in experiment is 80GPa and in MD simulation is 40GPa. The decreasing rate of Young’s modulus is about 22MPa/K. Since the formation and propagation of shear bands in metallic glasses dominate their mechanical properties, we perform three-dimensional atomic-strain calculations, and study the connections between the strain localization and propagation of shear bands under the indenter tip. In addition, higher loading rates decrease hardness, and cause larger disturbed regions under the indent, and enlarge shear-banding patterns.

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