本文之研究主要是利用霍普金森撞擊試驗機，來探討Fe-2Ni粉末冶金件於高速撞擊下之塑性變形行為。實驗測試於室溫25℃，及應變速率分別為2500s-1、3250 s-1、4300 s-1、5550 s-1、8300s-1下進行，藉實驗數據和微觀結果，以瞭解應變速率對Fe-2Ni粉末冶金件的動態機械特性及相對微觀組織變化之影響。同時引用一合適之材料構成方程式，來描述Fe-2Ni粉末冶金件的常溫高速之塑變行為，以做為工程模擬與分析之用。
　　實驗結果顯示，應變速率及應變量對Fe-2Ni粉末冶金件的機械性質影響甚鉅，其塑流應力值隨著應變速率的增加而上升，且隨著應變量的增加而上升。相同地，其熱活化體積亦會隨著應變速率之增加而上升，而應變速率敏感性係數及加工硬化率則有相反之趨勢。隨著應變量的增加，加工硬化率及應變速率敏感性皆呈現下降的趨勢，而熱活化體積則會上升。由OM觀察可知，隨著應變速率的增加，晶粒有細化的現象。最後，藉由Khan-Huang-Liang模式之構成方程式，其可以很精確的來描述Fe-2Ni粉末冶金件於常溫高速撞擊下之塑變行為。

　　This study uses a Split-Hopkinson bar to investigate the plastic deformation behaviour of Fe-2Ni Alloy Powder Compacts subjected to high strain rate loading. The present tests are performed under strain rates ranging from 2500s-1 to 6830s-1 at room temperature. Optical microscopy techniques are used to analyze the microstructure characteristics of the deformed specimens in order to determine the relationship between the mechanical and microstructural properties of Fe-2Ni Alloy Powder Compacts . The experimental results indicate that the mechanical properties of Fe-2Ni Alloy Powder Compacts depend significantly on the strain rates and strains. At room temperature, the flow stress and activation volume increase with increasing strain rate, while the strain rate sensitivity and work hardening coefficient decrease. OM analysis reveals that the grain size decreases as the strain rate increases. Finally, it is shown that the Khan-Huang-Liang constitutive equation with the experimentally determined specific material parameters successfully describes the plastic flow behaviour of Fe-2Ni Alloy Powder Compacts under the current test conditions.

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