本論文目的為研究鋁鈧合金在高應變速率荷載情況下之撞擊變形行為，我們使用壓縮式霍普金森桿進行機械測試，訂應變速率條件為1200 s-1、3200 s-1和5800 s-1，及溫度條件為-100℃、25℃和300℃。
　　實驗結果顯示，鋁鈧合金之塑流應力值、加工硬化率、應變速率敏感性係數及熱活化體積皆會隨著應變量、應變速率和溫度範圍之變異而改變。固定溫度條件時，塑流應力值、加工硬化率以及應變速率敏感性係數皆會隨應變速率增加而增益，而熱活化體積則會下降。另一方面，固定應變速率時，塑流應力值、加工硬化率與應變速率敏感性係數會循溫度上升而變小，但是熱活化體積卻會增大。另外，我們論證Zerilli-Armstrong構成方程式，其可針對鋁鈧合金之撞擊變形行為提供精確之預測。
　　光學式電子顯微鏡之微觀結構分析可發現試件中有絕熱剪切帶形成，且剪切帶寬度會受到應變速率和溫度之影響。另外，掃描式電子顯微鏡之金相斷面觀察則可顯見破壞面具有韌窩組織特徵，該韌窩之外觀與密度取決於應變速率與溫度條件。除此之外，穿透式電子顯微鏡之微觀結構觀察可發覺差排密度、差排圈尺寸皆與應變速率、塑流應力值及溫度條件相關。最後，基地中之Al3Sc析出物可阻檔差排之移動遂導致強化材料之效果。

　　This paper employs a compressive split-Hopkinson bar to investigate the impact deformation behavior of Al-Sc alloy under high strain rate loading conditions of 1200 s-1, 3200 s-1 and 5800 s-1, respectively, at temperatures of -100℃, 25℃and 300℃. The experimental results indicate that the flow stress, work hardening rate, strain rate sensitivity and activation volume of Al-Sc alloy are all dependent on the strain, strain rate and testing temperature. For a constant temperature, the flow stress, work hardening rate and strain rate sensitivity increase with increasing strain rate, while the activation volume decreases. Conversely, for a constant strain rate, the flow stress, work hardening rate and strain rate sensitivity decrease with increasing temperature, while the activation volume increases. It is found that the impact deformation behaviour of Al-Sc alloy can be accurately described using the Zerilli-Armstrong constitutive equation.
　　Optical microscopy analyses reveal that adiabatic shear bands are formed in all the impacted specimens. The width of these shear bands is determined by the applied strain rate and temperature conditions. Furthermore, scanning electron microscopy fractographic observations show that the fracture surfaces are characterised by a dimple-like structure. The appearance and density of the dimples are strongly related to the strain rate and temperature. Transmission electron microscopy observations indicate that the dislocation density and cell size are related to the strain rate, flow stress and temperature. Finally, the Al3Sc precipitations in the matrix suppress dislocation motion and prompt a significant strengthening effect.

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