本論文主要是使用霍普金森桿撞擊試驗機，分別於不同溫度和高應變速率荷載下測試Inconel 625合金之塑性變形行為下的機械性質及微觀結構變化。分別於應變速率3700s-1、5000s-1和6400s-1及實驗溫度25℃、300℃、750℃下進行試驗，以了解溫度及應變速率對材料塑變行為及微觀結構之影響。
實驗結果指出，Inconel 625合金在相同溫度條件下，其塑流應力值、加工硬化率及應變速率敏感性係數均會隨應變速率之增加而上升，而熱活化體積則會下降。相反地，在相同應變速率條件下，其塑流應力值、加工硬化率與應變速率敏感性係數則會隨溫度之增加而下降，而熱活化體積則會上升。此外，可以藉由Zerilli-Armstrong構成方程式，來精確的預測此合金在不同溫度及應變速率下的塑變行為。
在微觀方面，由光學顯微鏡之觀測，可以觀察到Inconel 625合金經過撞擊後有MC與M23C6碳化物之析出，並且於750℃之實驗條件下出現沿晶破壞；在穿透式電子顯微鏡下則可觀測到原本散亂在母材之差排，遭受撞擊後，差排會糾結在一起，且差排密度會隨著應變速率上升和溫度降低而增加，其關聯性可用Bailey-Hirsch type關係式來描述。

Dynamic impact response and microstructural characteristics of Inconel 625 alloy are investigated under strain rates ranging from 3700s−1 to 6400s−1 and different temperatures of 25ºC, 300ºC and 750ºC, respectively, using a compressive split-Hopkinson pressure bar. The results indicate that mechanical properties of Inconel 625 alloy are sensitive to temperature and strain rate. At a constant temperature, flow stress, work hardening rate, strain rate sensitivity and temperature sensitivity all increase, but the thermal activation volume and activation energy decrease with the increasing strain rate. However, at a constant strain rate, flow stress, work hardening rate, strain rate sensitivity, and temperature sensitivity decrease but the thermal activation volume and activation energy increase with increasing temperature. A Zerilli-Armstrong constitutive equation is used to describe the deformation behavior of Inconel 625 alloy under tested conditions. Optical Microscope(OM) observations reveal that there are MC and M23C6 carbides participated in Inconel 625 alloy. The intergranular crack and failure are observed under 750ºC condition. Furthermore, Transmission Electron Microscopy(TEM) observations show that the dislocation density increases with increasing strain rate, but decreases with increasing temperature. The relationship between the dislocation density and the stress can be expressed using the Bailey-Hirsch equation.

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